Furoquinolinediones as inhibitors of tdp2

ABSTRACT

Compounds of Formula I and the pharmaceutically acceptable salts thereof are disclosed 
     
       
         
         
             
             
         
       
     
     The variables X 1 , X 2 , and R 1-4  are disclosed herein. The compounds are useful for treating cancer and related proliferative diseases. Pharmaceutical compositions containing compounds of Formula I and methods of treatment comprising administering compounds of Formula I are also disclosed.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation application of U.S. application Ser. No.15/542,560, filed on Jul. 10, 2018, which claims priority fromPCT/US16/012,672, filed on Jan. 8, 2016, which claims priority from U.S.Provisional Application No. 62/100,968, filed Jan. 8, 2015, the contentsof which are hereby incorporated by reference in their entirety.

STATEMENT OF GOVERNMENT SUPPORT

This invention was made in part with government support from theNational Institutes of Health. The government has certain rights in thisinvention.

BACKGROUND

Topoisomerases are a family of enzymes essential for relaxation ofsupercoiled DNA, required for transcription, replication, and chromosomesegregation. Topoisomerases cleave the supercoiled nucleic acids, whichrelieves torsional strain, and then religate the cut strands. Theessential role of toposiomerases in DNA replication has made theseenzymes major targets for cancer therapy. Topoisomerase inhibitors, suchas camptothecin and topotecan for topoisomerase 1(Top1), and etoposideand doxorubicin for topoisomerase 2 (Top2), trap topoisomerase-DNAcleavage complexes, thereby preventing replication and triggeringdestruction by apoptosis.

Tyrosyl-DNA phosphodiesterases (TDPs) play an important role in therepair of trapped topoisomerase-DNA cleavage complexes. TDPs exist intwo forms: TDP1, for resolving trapped Top1-DNA cleavage complexes, andTDP2, for resolving Top2-DNA cleavage complexes.

Because TDPs can repair a broad spectrum of nucleic acid lesions,inhibition of TDPs is an attractive target for therapeutic treatment ofcancers, possibly as sole therapeutic agents. It has also been notedthat TDP2 deficiency potentiates the antiproliferative activity of Top2inhibitors in cells with defective cell checkpoints, thus TDP2inhibitors may provide synergistic effects as a combination therapy withinhibitors of Top2, such as etoposide and doxorubicin. Similarsynergistic effects would be expected with inhibitors of Top1 and TDP1.Therefore, identifying effective inhibitors of TDP1 and/or TDP2 would beimportant in providing new methods of treating cancer.

SUMMARY

Described herein are inhibitors of TDP2, their methods of manufacture,compositions containing the described compounds, and methods of use ofthe described compounds. In a first aspect, a compound of Formula I andthe pharmaceutically acceptable salts of a compound of Formula I areprovided

within Formula I the following conditions are met.

X¹ is N or CR.

X² is N or CR⁶.

At least one of X¹ or X² is N.

R¹ is hydroxyl, C₁-C₆alkyl, C₁-C₆alkoxy, C₂-C₆alkenyloxy,C₂-C₆alkynyloxy, or C₃-C₇cycloalkyloxy, where one or more methyleneunits in the alkyl, alkenyl, or alkynyl portion of R¹ is optionally andindependently replaced with —O—, —S—, or —N(R⁷)—, and R¹ other thanhydroxyl is substituted by 0-3 substituents independently chosen at eachoccurrence from halogen, hydroxyl, cyano, ═N, ═NOR⁷, —CO₂H,—(CO)—O—C₁-C₆alkyl, —C(O)NR⁷R⁸, and —W—P(O)YR⁹ZR¹⁰.

Or R¹ can be —O-A-B, wherein O is an oxygen atom.

A is a linker consisting of a bond, an alkylene chain of 1 to 6 carbons,or a phenylene group.

B is a phenyl, or a 5 or 6 membered heterocycle having 1, 2, or 3 ringatoms independently chosen from N, O, and S, wherein B is substitutedwith 0-3 substituents independently chosen from halogen, hydroxyl,cyano, amino, —SH, C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl, C₁-C₆alkoxy,C₂-C₆alkanoyl, C₁-C₆thioalkyl, C₁-C₆haloalkyl, C₁-C₆haloalkoxy,—(C₀-C₆alkyl)cycloalkyl, —(C₀-C₆alkyl)CO₂H,—(C₀-C₆alkyl)-(CO)—O—C₁-C₆alkyl, —(C₀-C₆alkyl)C(O)NR⁷R⁸,—(C₀-C₆alkyl)NR⁷C(O)R⁸, —(C₁-C₆alkyl)alkoxy, —(C₁-C₆alkyl)OH,—(C₀-C₆alkyl)NR⁷R⁸, —SO₂—C₁-C₆alkyl, and —(C₀-C₆alkyl)-W—P(O)YR⁹ZR¹⁰.

Y¹ is O, NH, or S.

Y² is Nor CR².

R² is hydrogen, halogen, C₁-C₆alkyl, C₁-C₆alkoxy, C₁-C₆haloalkyl,C₁-C₆haloalkoxy, —(C₀-C₆alkyl)cycloalkyl, —(C₀-C₆alkyl)NR⁷R⁸, or phenyl,each R² other than hydrogen and hydroxyl being substituted with 0 to 3groups chosen independently at each occurrence from halogen, hydroxyl,C₁-C₆alkyl, C₁-C₆alkoxy, C₁-C₆haloalkyl, and C₁-C₆haloalkoxy.

Or, R² is a group -J-Q, where J is a 1 to 4 carbon alkylene linker inwhich any —CH₂— group is optionally replaced by —C(O)O—, —C(O)NH—,—C(O)NR¹¹, or —C(O)—.

Q is C₁-C₆alkyl, C₁-C₆alkylamino, aryl, or heteroaryl, each of which isunsubstituted or substituted with one or more groups independentlychosen from halogen, hydroxyl, amino, cyano, C₁-C₄alkyl, C₁-C₄alkoxy,C₁-C₂haloalkyl, and C₁-C₂haloalkoxy.

W, Y, and Z are independently at each occurrence a bond or O.

R³, R⁴, R⁵, and R⁶, are chosen independently at each occurrence fromhydrogen, halogen, cyano, amino, C₁-C₆alkyl, —(C₀-C₆alkyl)cycloalkyl,C₁-C₆alkoxy, C₁-C₆haloalkyl, and C₁-C₆haloalkoxy.

R⁷, R⁸, R⁹ and R¹⁰ are chosen independently at each occurrence fromhydrogen, C₁-C₆alkyl, C₂-C₆alkenyl, —(C₀-C₆alkyl)cycloalkyl, andC₁-C₆haloalkyl, and any R⁷ and R⁸ bound to the same nitrogen atom may betaken together to form a 4- to 7-membered heterocyloalkyl groupsubstituted with 0 to 2 substituents chosen from hydroxyl, halogen,C₁-C₄alkyl, C₁-C₄alkoxy, and C₂-C₄alkanoyl.

R¹¹ is C₁-C₆alkyl or C₁-C₆alkylamino.

Wherein the compound is not:

Pharmaceutical compositions comprising a compound or salt of Formula Itogether with a pharmaceutically acceptable carrier are also disclosed.

Methods of treating a cancer responsive to TDP2 inhibition, comprisingthe step of administering to the patient in need thereof a compound orsalt thereof, are also disclosed.

Methods of treating cancers, including glioma (glioblastoma), acutemyelogenous leukemia, acute myeloid leukemia,myelodysplastic/myeloproliferative neoplasms, sarcoma, chronicmyelomonocytic leukemia, non-Hodgkin's lymphoma, astrocytoma, melanoma,non-small cell lung cancer, small cell lung cancer, cervical cancer,rectal cancer, ovarian cancer, cholangiocarcinomas, chondrosarcoma, orcolon cancer, comprising administering a therapeutically effectiveamount of a compound or salt of Formula I to a patient in need of suchtreatment are also disclosed.

DETAILED DESCRIPTION Terminology

Compounds are described using standard nomenclature. Unless definedotherwise, all technical and scientific terms used herein have the samemeaning as is commonly understood by one of skill in the art to whichthis invention belongs.

The terms “a” and “an” do not denote a limitation of quantity, butrather denote the presence of at least one of the referenced items. Theterm “or” means “and/or”. The terms “comprising,” “having,” “including,”and “containing” are to be construed as open-ended terms (i.e., meaning“including, but not limited to”).

Recitation of ranges of values are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. The endpoints of all ranges are includedwithin the range and independently combinable.

All methods described herein can be performed in a suitable order unlessotherwise indicated herein or otherwise clearly contradicted by context.The use of any and all examples, or exemplary language (e.g., “suchas”), is intended merely to better illustrate the invention and does notpose a limitation on the scope of the invention unless otherwiseclaimed. No language in the specification should be construed asindicating any non-claimed element as essential to the practice of theinvention as used herein. Unless defined otherwise, technical andscientific terms used herein have the same meaning as is commonlyunderstood by one of skill in the art of this disclosure.

Furthermore, the disclosure encompasses all variations, combinations,and permutations in which one or more limitations, elements, clauses,and descriptive terms from one or more of the listed claims areintroduced into another claim. For example, any claim that is dependenton another claim can be modified to include one or more limitationsfound in any other claim that is dependent on the same base claim. Whereelements are presented as lists, e.g., in Markush group format, eachsubgroup of the elements is also disclosed, and any element(s) can beremoved from the group.

All compounds are understood to include all possible isotopes of atomsoccurring in the compounds. Isotopes include those atoms having the sameatomic number but different mass numbers. By way of general example, andwithout limitation, isotopes of hydrogen include tritium and deuteriumand isotopes of carbon include ¹¹C, ¹³C, and ¹⁴C.

Formula I includes all pharmaceutically acceptable salts of Formula I.

The opened ended term “comprising” includes the intermediate and closedterms “consisting essentially of” and “consisting of.”

The term “substituted” means that any one or more hydrogens on thedesignated atom or group is replaced with a selection from the indicatedgroup, provided that the designated atom's normal valence is notexceeded. When the substituent is oxo (i.e., ═O), then 2 hydrogens onthe atom are replaced. When aromatic moieties are substituted by an oxogroup, the aromatic ring is replaced by the corresponding partiallyunsaturated ring. For example a pyridyl group substituted by oxo is apyridone. Combinations of substituents and/or variables are permissibleonly if such combinations result in stable compounds or useful syntheticintermediates. A stable compound or stable structure is meant to imply acompound that is sufficiently robust to survive isolation from areaction mixture, and subsequent formulation into an effectivetherapeutic agent.

Suitable groups that may be present on an “optionally substituted”position include, but are not limited to, e.g., halogen, cyano,hydroxyl, amino, nitro, oxo, azido, alkanoyl (such as a C₂-C₆ alkanoylgroup such as acyl or the like (—(CO)alkyl)); carboxamido;alkylcarboxamide; alkyl groups, alkoxy groups, alkylthio groupsincluding those having one or more thioether linkages, alkylsulfinylgroups including those having one or more sulfinyl linkages,alkylsulfonyl groups including those having one or more sulfonyllinkages, mono- and di-aminoalkyl groups including groups having one ormore N atoms, all of the foregoing optional alkyl substituents may haveone or more methylene groups replaced by an oxygen or —NH—, and havefrom about 1 to about 8, from about 1 to about 6, or from 1 to about 4carbon atoms, cycloalkyl; phenyl; phenylalkyl with benzyl being anexemplary phenylalkyl group, phenylalkoxy with benzyloxy being anexemplary phenylalkoxy group. Alkylthio and alkoxy groups are attachedto the position they substitute by the sulfur or oxygen atomrespectively.

A dash (“-”) that is not between two letters or symbols is used toindicate a point of attachment for a substituent.

“Alkyl” includes both branched and straight chain saturated aliphatichydrocarbon groups, having the specified number of carbon atoms,generally from 1 to about 8 carbon atoms. The term C₁-C₆alkyl as usedherein indicates an alkyl group having from 1, 2, 3, 4, 5, or 6 carbonatoms. Other embodiments include alkyl groups having from 1 to 8 carbonatoms, 1 to 4 carbon atoms or 1 or 2 carbon atoms, e.g. C₁-C₆alkyl,C₁-C₄alkyl, and C₁-C₂alkyl. When C₀-C_(n) alkyl is used herein inconjunction with another group, for example, —C₀-C₂alkyl(phenyl), theindicated group, in this case phenyl, is either directly bound by asingle covalent bond (C₀alkyl), or attached by an alkyl chain having thespecified number of carbon atoms, in this case 1, 2, 3, or 4 carbonatoms. Alkyls can also be attached via other groups such as heteroatomsas in —O—C₀-C₄alkyl(C₃-C₇cycloalkyl). Examples of alkyl include, but arenot limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl,3-methylbutyl, t-butyl, n-pentyl, and sec-pentyl.

“Alkenyl” is a branched or straight chain aliphatic hydrocarbon grouphaving one or more carbon-carbon double bonds that may occur at anystable point along the chain, having the specified number of carbonatoms. Examples of alkenyl include, but are not limited to, ethenyl andpropenyl.

“Alkynyl” is a branched or straight chain aliphatic hydrocarbon grouphaving one or more double carbon-carbon triple bonds that may occur atany stable point along the chain, having the specified number of carbonatoms.

“Alkoxy” is an alkyl group as defined above with the indicated number ofcarbon atoms covalently bound to the group it substitutes by an oxygenbridge (—O—). Examples of alkoxy include, but are not limited to,methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, 2-butoxy, t-butoxy,n-pentoxy, 2-pentoxy, 3-pentoxy, isopentoxy, neopentoxy, n-hexoxy,2-hexoxy, 3-hexoxy, and 3-methylpentoxy. Similarly an “Alkylthio” or a“thioalkyl” group is an alkyl group as defined above with the indicatednumber of carbon atoms covalently bound to the group it substitutes by asulfur bridge (—S—). Similarly, “alkenyloxy”, “alkynyloxy”, and“cycloalkyloxy” refer to alkenyl, alkynyl, and cycloalkyl groups, ineach instance covalently bound to the group it substitutes by an oxygenbridge (—O—).

“Alkanoyl” is an alkyl group as defined above with the indicated numberof carbon atoms covalently bound to the group it substitutes via keto(—C(O)—) group. The carbon of the keto group is included in the numberof carbon atoms in the alkanoyl group, i.e. C₂ alkanoyl is —C(O))CH₃.

“Alkylene” is a chain of one or more methylene groups with attachmentpoints on each end such that it can link two other groups, i.e. thealkylene group is —(CH₂)_(n)—.

“Cycloalkyl” is a saturated hydrocarbon ring group, having the specifiednumber of carbon atoms, usually from 3 to about 7 carbon atoms. Examplesof cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, orcyclohexyl as well as bridged or caged saturated ring groups such asnorborane or adamantane. “—(C₀-C_(n)alkyl)cycloalkyl” is a cycloalkylgroup attached to the position it substitutes either by a singlecovalent bond (C₀) or by an alkylene linker having 1 to n carbon atoms.

“Halo” or “halogen” means fluoro, chloro, bromo, or iodo.

“Heteroaryl” is a stable monocyclic aromatic ring having the indicatednumber of ring atoms which contains from 1 to 3, or in some embodimentsfrom 1 to 2, heteroatoms chosen from N, O, and S, with remaining ringatoms being carbon, or a stable bicyclic or tricyclic system containingat least one 5- to 7-membered aromatic ring which contains from 1 to 3,or in some embodiments from 1 to 2, heteroatoms chosen from N, O, and S,with remaining ring atoms being carbon. Monocyclic heteroaryl groupstypically have from 5 to 7 ring atoms. In some embodiments bicyclicheteroaryl groups are 9- to 10-membered heteroaryl groups, that is,groups containing 9 or 10 ring atoms in which one 5- to 7-memberaromatic ring is fused to a second aromatic or non-aromatic ring. Whenthe total number of S and O atoms in the heteroaryl group exceeds 1,these heteroatoms are not adjacent to one another. It is preferred thatthe total number of S and O atoms in the heteroaryl group is not morethan 2. It is particularly preferred that the total number of S and Oatoms in the aromatic heterocycle is not more than 1. Heteroaryl groupsinclude, but are not limited to, oxazolyl, piperazinyl, pyranyl,pyrazinyl, pyrazolopyrimidinyl, pyrazolyl, pyridizinyl, pyridyl,pyrimidinyl, pyrrolyl, quinolinyl, tetrazolyl, thiazolyl,thienylpyrazolyl, thiophenyl, triazolyl, benzo[d]oxazolyl, benzofuranyl,benzothiazolyl, benzothiophenyl, benzoxadiazolyl, dihydrobenzodioxynyl,furanyl, imidazolyl, indolyl, and isoxazolyl.

“Heterocycle” is a saturated, unsaturated, or aromatic cyclic grouphaving the indicated number of ring atoms containing from 1 to about 3heteroatoms chosen from N, O, and S, with remaining ring atoms beingcarbon. Examples of heterocycle groups include piperazine and thiazolegroups.

“Heterocycloalkyl” is a saturated cyclic group having the indicatednumber of ring atoms containing from 1 to about 3 heteroatoms chosenfrom N, O, and S, with remaining ring atoms being carbon. Examples ofheterocycloalkyl groups include tetrahydrofuranyl and pyrrolidinylgroups.

“Haloalkyl” means both branched and straight-chain alkyl groups havingthe specified number of carbon atoms, substituted with 1 or more halogenatoms, generally up to the maximum allowable number of halogen atoms.Examples of haloalkyl include, but are not limited to, trifluoromethyl,difluoromethyl, 2-fluoroethyl, and penta-fluoroethyl.

“Haloalkoxy” is a haloalkyl group as defined above attached through anoxygen bridge (oxygen of an alcohol radical).

“Phenylene” is a benzene ring with two different attachment points suchthat it can link two other groups, i.e. the phenylene group is —(C₆H₄)—.The attachment points can be ortho., meta, or para to each other.

“Pharmaceutical compositions” means compositions comprising at least oneactive agent, such as a compound or salt of Formula I, and at least oneother substance, such as a carrier. Pharmaceutical compositions meet theU.S. FDA's GMP (good manufacturing practice) standards for human ornon-human drugs.

“Carrier” means a diluent, excipient, or vehicle with which an activecompound is administered. A “pharmaceutically acceptable carrier” meansa substance, e.g., excipient, diluent, or vehicle, that is useful inpreparing a pharmaceutical composition that is generally safe, non-toxicand neither biologically nor otherwise undesirable, and includes acarrier that is acceptable for veterinary use as well as humanpharmaceutical use. A “pharmaceutically acceptable carrier” includesboth one and more than one such carrier.

A “patient” means a human or non-human animal in need of medicaltreatment. Medical treatment can include treatment of an existingcondition, such as a disease or disorder or diagnostic treatment. Insome embodiments the patient is a human patient.

“Providing” means giving, administering, selling, distributing,transferring (for profit or not), manufacturing, compounding, ordispensing.

“Treatment” or “treating” means providing an active compound to apatient in an amount sufficient to measurably reduce any cancer symptom,slow cancer progression or cause cancer regression. In certainembodiments treatment of the cancer may be commenced before the patientpresents symptoms of the disease.

A “therapeutically effective amount” of a pharmaceutical compositionmeans an amount effective, when administered to a patient, to provide atherapeutic benefit such as an amelioration of symptoms, decrease cancerprogression, or cause cancer regression.

A significant change is any detectable change that is statisticallysignificant in a standard parametric test of statistical significancesuch as Student's T-test, where p<0.05.

Chemical Description

Compounds of Formula I may contain one or more asymmetric elements suchas stereogenic centers, stereogenic axes and the like, e.g., asymmetriccarbon atoms, so that the compounds can exist in differentstereoisomeric forms. These compounds can be, for example, racemates oroptically active forms. For compounds with two or more asymmetricelements, these compounds can additionally be mixtures of diastereomers.For compounds having asymmetric centers, all optical isomers in pureform and mixtures thereof are encompassed. In these situations, thesingle enantiomers, i.e., optically active forms can be obtained byasymmetric synthesis, synthesis from optically pure precursors, or byresolution of the racemates. Resolution of the racemates can also beaccomplished, for example, by conventional methods such ascrystallization in the presence of a resolving agent, or chromatography,using, for example a chiral HPLC column. All forms are contemplatedherein regardless of the methods used to obtain them.

All forms (for example solvates, optical isomers, enantiomeric forms,polymorphs, free compound and salts) of an active agent may be employedeither alone or in combination.

The term “chiral” refers to molecules, which have the property ofnon-superimposability of the mirror image partner.

“Stereoisomers” are compounds, which have identical chemicalconstitution, but differ with regard to the arrangement of the atoms orgroups in space.

A “diastereomer” is a stereoisomer with two or more centers of chiralityand whose molecules are not mirror images of one another. Diastereomershave different physical properties, e.g., melting points, boilingpoints, spectral properties, and reactivities.

Mixtures of diastereomers may separate under high resolution analyticalprocedures such as electrophoresis, crystallization in the presence of aresolving agent, or chromatography, using, for example a chiral HPLCcolumn.

“Enantiomers” refer to two stereoisomers of a compound, which arenon-superimposable mirror images of one another. A 50:50 mixture ofenantiomers is referred to as a racemic mixture or a racemate, which mayoccur where there has been no stereoselection or stereospecificity in achemical reaction or process.

Stereochemical definitions and conventions used herein generally followS. P. Parker, Ed., McGraw-Hill Dictionary of Chemical Terms (1984)McGraw-Hill Book Company, New York; and Eliel, E. and Wilen, S.,Stereochemistry of Organic Compounds (1994) John Wiley & Sons, Inc., NewYork. Many organic compounds exist in optically active forms, i.e., theyhave the ability to rotate the plane of plane-polarized light. Indescribing an optically active compound, the prefixes D and L or R and Sare used to denote the absolute configuration of the molecule about itschiral center(s). The prefixes d and l or (+) and (−) are employed todesignate the sign of rotation of plane-polarized light by the compound,with (−) or l meaning that the compound is levorotatory. A compoundprefixed with (+) or d is dextrorotatory.

A “racemic mixture” or “racemate” is an equimolar (or 50:50) mixture oftwo enantiomeric species, devoid of optical activity. A racemic mixturemay occur where there has been no stereoselection or stereospecificityin a chemical reaction or process.

“Pharmaceutically acceptable salts” include derivatives of the disclosedcompounds in which the parent compound is modified by making inorganicand organic, non-toxic, acid or base addition salts thereof. The saltsof the present compounds can be synthesized from a parent compound thatcontains a basic or acidic moiety by conventional chemical methods.Generally, such salts can be prepared by reacting free acid forms ofthese compounds with a stoichiometric amount of the appropriate base(such as Na, Ca, Mg, or K hydroxide, carbonate, bicarbonate, or thelike), or by reacting free base forms of these compounds with astoichiometric amount of the appropriate acid. Such reactions aretypically carried out in water or in an organic solvent, or in a mixtureof the two. Generally, non-aqueous media such as ether, ethyl acetate,ethanol, isopropanol, or acetonitrile are used, where practicable. Saltsof the present compounds further include solvates of the compounds andof the compound salts.

Examples of pharmaceutically acceptable salts include, but are notlimited to, mineral or organic acid salts of basic residues such asamines; alkali or organic salts of acidic residues such as carboxylicacids; and the like. The pharmaceutically acceptable salts include theconventional non-toxic salts and the quaternary ammonium salts of theparent compound formed, for example, from non-toxic inorganic or organicacids. For example, conventional non-toxic acid salts include thosederived from inorganic acids such as hydrochloric, hydrobromic,sulfuric, sulfamic, phosphoric, nitric and the like; and the saltsprepared from organic acids such as acetic, propionic, succinic,glycolic, stearic, lactic, malic, tartaric, citric, ascorbic, pamoic,maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic,mesylic, esylic, besylic, sulfanilic, 2-acetoxybenzoic, fumaric,toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic,HOOC—(CH₂)_(n)—COOH where n is 0-4, and the like. Lists of additionalsuitable salts may be found, e.g., in G. Steffen Paulekuhn, et al.,Journal of Medicinal Chemistry 2007, 50, 6665 and Handbook ofPharmaceutically Acceptable Salts: Properties, Selection and Use, P.Heinrich Stahl and Camille G. Wermuth, Editors, Wiley-VCH, 2002.

TDP2 Inhibitors

Molecules which inhibit TDP2 are disclosed herein.

In addition to compounds of Formula I shown in the SUMMARY section, thedisclosure also includes compounds in which the variables, e.g. A, B,X¹, X², W, Y, Z, R¹ to R¹⁰ carry the following definitions. Thedisclosure includes all combinations of these definitions so long as astable compound results. The disclosure includes the followingparticular embodiments of Formula (I).

The disclosure includes compounds of Formula IA and IB and saltsthereof.

R¹ is hydroxyl, C₁-C₈alkoxy or —O—(C₀-C₆alkyl)cycloalkyl, in which oneor more methylene units in the alkoxy or alkyl portion of R¹ isoptionally and independently replaced with —O— or —N(R⁷)—, and R¹ issubstituted by 0-3 substituents independently chosen at each occurrencefrom hydroxyl, halogen, cyano, —CO₂H, —(CO)—O—C₁-C₆alkyl, and—W—P(O)YR⁹ZR¹⁰; or R¹ is —O-A-B.

B is a phenyl, or a 5 or 6 membered heteroaryl having 1, 2, or 3Nitrogen ring atoms, wherein B is optionally substituted with 0-3substituents independently chosen from halogen, hydroxyl, cyano, amino,C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl, C₂-C₆alkanoyl, C₁-C₆alkoxy,C₁-C₆haloalkyl, C₁-C₆haloalkoxy, —(C₀-C₆alkyl)cycloalkyl,—(C₀-C₆alkyl)CO₂H, —(C₀-C₆alkyl)-(CO)—O—C₁-C₆alkyl, —(C₁-C₆alkyl)alkoxy,—(C₁-C₆alkyl)OH, —SO₂—C₁-C₆alkyl, and —(C₀-C₆alkyl)-W—P(O)YR⁹ZR¹⁰.

R² is halogen, C₁-C₆alkyl, C₁-C₆haloalkyl, or —(C₀-C₆alkyl)cycloalkyl,or phenyl, said phenyl being substituted with 0 to 3 groups chosenindependently at each occurrence from halogen, hydroxyl, C₁-C₆alkyl,C₁-C₆alkoxy, C₁-C₆haloalkyl, and C₁-C₆haloalkoxy.

(B) R³ and R⁴ are both hydrogen.

(C) R² is C₁-C₆alkyl, C₁-C₆haloalkyl, —(C₀-C₆alkyl)cycloalkyl, orphenyl, said phenyl being substituted with 0 to 3 groups chosenindependently at each occurrence from halogen, hydroxy, C₁-C₆alkyl,C₁-C₆alkoxy, C₁-C₆haloalkyl, and C₁-C₆haloalkoxy. (D) R¹ is substitutedwith at least one —W—P(O)YR⁹ZR¹⁰ substituent; and

W is a bond, and Y and Z are both O.

(E) R² is methyl or phenyl.

(F) X¹ is N and X² is CH.

(G) X¹ is CH and X² is N.

(H) R¹ is C₁-C₈alkoxy.

R¹ is a phenoxy or pyridyloxy, each of which is optionally substitutedwith 0-3 substituents independently chosen from halogen, hydroxyl,cyano, C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl, C₁-C₆alkoxy,C₁-C₆haloalkyl, C₁-C₆haloalkoxy, —(C₀-C₆alkyl)cycloalkyl,—(C₀-C₆alkyl)CO₂H, —(C₀-C₆alkyl)-(CO)—O—C₁-C₆alkyl, —(C₁-C₆alkyl)alkoxy,—(C₁-C₆alkyl)OH, —SO₂—C₁-C₆alkyl, and —(C₀-C₆alkyl)-W—P(O)YR⁹ZR¹⁰.

(I) R¹ is alkoxy where one or more methylene units in the alkyl portionof R¹ is optionally replaced by —O— or —N(R⁷)— and R¹ is substitutedwith 1 to 3 substituents independently chosen from hydroxyl and—WP(O)YR⁹ZR¹⁰; where W is a bond; and Y and Z are both O.

(J) R¹ is —O-A-B.

(K) R¹ is —O-A-B;

A is a bond or an alkylene chain of 1 to 3 carbon atoms; and

B is phenyl or pyridyl optionally substituted with 0-3 substituentsindependently chosen from halogen, hydroxyl, cyano, C₁-C₄alkyl,C₁-C₄alkoxy, C₂-C₄alkanoyl, C₁-C₂haloalkyl, C₁-C₂haloalkoxy,—(C₀-C₂alkyl)-(CO)—O—C₁-C₆alkyl, —(C₀-C₂alkyl)C(O)NR⁷R⁸,—(C₀-C₂alkyl)NR⁷C(O)R⁸, —(C₁-C₆alkyl)OH, and —SO₂—C₁-C₂alkyl.

(L) R¹ is —O-A-B;

A is a bond; and

B is phenyl substituted with one substituent chosen from hydroxyl,halogen, and cyano.

(M) R¹ is —O-A-B; and

B is a triazolyl, pyrazolyl, imidazolyl, thienyl, dioxylanyl,morpholinyl, piperazinyl, or piperidinyl group; each of which B issubstituted with 0-3 substituents independently chosen from halogen,hydroxyl, cyano, amino, C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl,C₁-C₆alkoxy, C₂-C₆alkanoyl, C₁-C₂haloalkyl, C₁-C₂haloalkoxy,—(C₀-C₆alkyl)CO₂H, —(C₀-C₆alkyl)-(CO)—O—C₁-C₆alkyl,—(C₀-C₆alkyl)C(O)NR⁷R⁸, —(C₀-C₆alkyl)NR⁷C(O)R⁸, —(C₁-C₆alkyl)OH,—(C₀-C₆alkyl)NR⁷R⁸, and —SO₂—C₁-C₆alkyl; where R⁷ and R⁸ are hydrogen orC₁-C₄alkyl.

(N) R² is hydrogen, halogen, C₁-C₆alkyl, C₁-C₆alkoxy, C₁-C₆haloalkyl,C₁-C₆haloalkoxy, —(C₀-C₆alkyl)cycloalkyl, —(C₀-C₆alkyl)NR⁷R⁸, or phenyl,each R² other than hydrogen and halogen being substituted with 0 to 3groups chosen independently at each occurrence from halogen, hydroxyl,C₁-C₆alkyl, C₁-C₆alkoxy, C₁-C₆haloalkyl, and C₁-C₆haloalkoxy.

(O) R² is

where n is 1, 2, 3, or 4;

J¹ is O, NH, NR¹¹;

Q¹ is C₁-C₆alkyl, or C₁-C₆alkylamino-;

R¹² is absent or 1 or more substituents independently chosen fromhydroxyl, halogen, amino, or cyano; and

R¹³ is absent or 1 or 2 substituents independently chosen fromC₁-C₄alkyl, and mono- or di-C₁-C₆alkylamino.

The disclosure includes an embodiment which is a pharmaceuticalcomposition comprising a compound or salt of Formula I, together with apharmaceutically acceptable carrier.

Pharmaceutical Preparations

Compounds disclosed herein can be administered as the neat chemical, butare preferably administered as a pharmaceutical composition.Accordingly, the disclosure provides pharmaceutical compositionscomprising a compound or pharmaceutically acceptable salt of a Tdp1inhibitor, such as a compound of Formula I, together with at least onepharmaceutically acceptable carrier. The pharmaceuticalcomposition/combination may contain a compound or salt of Formula I asthe only active agent, but is preferably contains at least oneadditional active agent. In certain embodiments it is preferred that theadditional active agent is compound or salt thereof chosen fromcamptothecin, irinotecan, and topotecan. In certain embodiments theadditional active agent is etoposide, teniposide, doxorubicin,daunorubicin, mitoxantrone, amsacrine, ellipticines, aurintricarboxylicacid, and3-hydroxy-2-[(1R)-6-isopropenyl-3-methyl-cyclohex-2-en-1-yl]-5-pentyl-1,4-benzoquinone(HU-331). In certain embodiments the pharmaceutical composition is in adosage form that contains from about 0.1 mg to about 2000 mg, from about10 mg to about 1000 mg, from about 100 mg to about 800 mg, or from about200 mg to about 600 mg of a compound of Formula I and optionally fromabout 0.1 mg to about 2000 mg, from about 10 mg to about 1000 mg, fromabout 100 mg to about 800 mg, or from about 200 mg to about 600 mg of anadditional active agent in a unit dosage form. The pharmaceuticalcomposition may also include a molar ratio of a compound of Tdp1inhibitor, such as a compound of Formula I, and an additional activeagent. For example the pharmaceutical composition may contain a molarratio of about 0.5:1, about 1:1, about 2:1, about 3:1 or from about1.5:1 to about 4:1 of an TDP2 inhibitor of Formula I to additionalactive agent.

Compounds disclosed herein may be administered orally, topically,parenterally, by inhalation or spray, sublingually, transdermally, viabuccal administration, rectally, as an ophthalmic solution, or by othermeans, in dosage unit formulations containing conventionalpharmaceutically acceptable carriers. The pharmaceutical composition maybe formulated as any pharmaceutically useful form, e.g., as an aerosol,a cream, a gel, a pill, a capsule, a tablet, a syrup, a transdermalpatch, or an ophthalmic solution. Some dosage forms, such as tablets andcapsules, are subdivided into suitably sized unit doses containingappropriate quantities of the active components, e.g., an effectiveamount to achieve the desired purpose.

Carriers include excipients and diluents and must be of sufficientlyhigh purity and sufficiently low toxicity to render them suitable foradministration to the patient being treated. The carrier can be inert orit can possess pharmaceutical benefits of its own. The amount of carrieremployed in conjunction with the compound is sufficient to provide apractical quantity of material for administration per unit dose of thecompound.

Classes of carriers include, but are not limited to binders, bufferingagents, coloring agents, diluents, disintegrants, emulsifiers,flavorants, glidants, lubricants, preservatives, stabilizers,surfactants, tableting agents, and wetting agents. Some carriers may belisted in more than one class, for example vegetable oil may be used asa lubricant in some formulations and a diluent in others. Exemplarypharmaceutically acceptable carriers include sugars, starches,celluloses, powdered tragacanth, malt, gelatin; talc, and vegetableoils. Optional active agents may be included in a pharmaceuticalcomposition, which do not substantially interfere with the activity ofthe compound of the present invention.

The pharmaceutical compositions/combinations can be formulated for oraladministration. These compositions contain between 0.1 and 99 weight %(wt. %) of a compound of Formula I and usually at least about 5 wt. % ofa compound of Formula I. Some embodiments contain from about 25 wt. % toabout 50 wt. % or from about 5 wt. % to about 75 wt. % of the compoundof Formula I.

Treatment Methods

The compounds of Formula I or a salt thereof, as well as pharmaceuticalcompositions comprising the compounds, are useful for treating cancer,including effecting tumor regression in vivo. The method of treatingcancer or effecting tumor regression comprises providing to a patient inneed of such treatment a therapeutically effective amount of a compoundof Formula I. In an embodiment the patient is a mammal, and morespecifically a human. The disclosure also provides methods of treatingnon-human patients such as companion animals, e.g. cats, dogs, andlivestock animals. A therapeutically effective amount of apharmaceutical composition may be an amount sufficient to inhibit theprogression of cancer or a cancerous tumor; or cause a regression of acancer or a cancerous tumor.

A therapeutically effective amount of a compound or pharmaceuticalcomposition described herein will also provide a sufficientconcentration of a compound of Formula I when administered to a patient.A sufficient concentration is a concentration of the compound in thepatient's body necessary to prevent or combat the disorder. Such anamount may be ascertained experimentally, for example by assaying bloodconcentration of the compound, or theoretically, by calculatingbioavailability.

Methods of treatment include providing certain dosage amounts of acompound of Formula I to a patient. Dosage levels of each compound offrom about 0.1 mg to about 140 mg per kilogram of body weight per dayare useful in the treatment of the above-indicated conditions (about 0.5mg to about 7 g per patient per day). The amount of compound that may becombined with the carrier materials to produce a single dosage form willvary depending upon the patient treated and the particular mode ofadministration. Dosage unit forms will generally contain between fromabout 1 mg to about 500 mg of each active compound. In certainembodiments 25 mg to 500 mg, or 25 mg to 200 mg of a compound of FormulaI are provided daily to a patient. Frequency of dosage may also varydepending on the compound used and the particular disease treated.However, for treatment of most diseases and disorders, a dosage regimenof 4 times daily or less can be used and in certain embodiments a dosageregimen of 1 or 2 times daily is used.

The compounds of Formula I may be used to treat cancers and effectregression of tumors, including cancerous tumors. In certainembodiments, the patient is suffering from a cell proliferative disorderor disease. The cell proliferative disorder can be cancer, tumor(cancerous or benign), neoplasm, neovascularization, or melanoma.Cancers for treatment include both solid and disseminated cancers.Exemplary solid cancers (tumors) that may be treated by the methodsprovided herein include e.g. cancers of the lung, prostate, breast,liver, colon, breast, kidney, pancreas, brain, skin including malignantmelanoma and Kaposi's sarcoma, testes or ovaries, carcinoma, sarcoma,and kidney cancer (renal cell). Cancers that may be treated with acompound of Formula I also include bladder cancer, breast cancer, coloncancer, endometrial cancer, lung cancer, bronchial cancer, melanoma,Non-Hodgkins lymphoma, cancer of the blood, pancreatic cancer, prostatecancer, thyroid cancer, brain or spinal cancer, and leukemia. Exemplarydisseminated cancers include leukemias or lymphoma including Hodgkin'sdisease, multiple myeloma and mantle cell lymphoma (MCL), chroniclymphocytic leukemia (CLL), T-cell leukemia, multiple myeloma, andBurkitt's lymphoma. Particularly included herein are methods of treatingcancer by providing a compound of Formula I to a patient wherein thecancer is a solid tumor or disseminated cancer.

Further included are methods of treating cancer by providing a compoundof Formula I to a patient wherein the cancer is selected from glioma(glioblastoma), acute myelogenous leukemia, acute myeloid leukemia,myelodysplastic/myeloproliferative neoplasms, sarcoma, chronicmyelomonocytic leukemia, non-Hodgkin's lymphoma, astrocytoma, melanoma,non-small cell lung cancer, small cell lung cancer, cervical cancer,rectal cancer, ovarian cancer, cholangiocarcinomas, chondrosarcoma, orcolon cancer.

It will be understood, however, that the specific dose level for anyparticular patient will depend upon a variety of factors including theactivity of the specific compound employed, the age, body weight,general health, sex, diet, time of administration, route ofadministration, and rate of excretion, drug combination and the severityof the particular disease undergoing therapy

A compound of Formula I may be administered singularly (i.e., soletherapeutic agent of a regime) to treat or prevent diseases andconditions such as undesired cell proliferation, cancer, and/or tumorgrowth or may be administered in combination with another active agent.One or more compounds of Formula I may be administered in coordinationwith a regime of one or more other chemotherapeutic agents such as anantineoplastic drug, e.g., an alkylating agent (e.g., mechloroethamine,chlorambucil, cyclophosamide, melphalan, or ifosfamide), anantimetabolite such as a folate antagonist (e.g., methotrexate), apurine antagonist (e.g. 6-mercaptopurine), or a pyrimidine antagonist(e.g., 5-fluorouracil). Other, non-limiting examples of chemotherapeuticagents that might be used in coordination with one or more compounds ofFormula I include taxanes and topoisomerase inhibitors. In addition,other non-limiting examples of active therapeutics include biologicalagents, such as monoclonal antibodies or IgG chimeric molecules, thatachieve their therapeutic effect by specifically binding to a receptoror ligand in a signal transduction pathway associated with cancer (e.g.therapeutic antibodies directed against CD20 (e.g. rituximab) or againstVEGF (e.g. bevacizumab)).

Methods of treatment provided herein are also useful for treatment ofmammals other than humans, including for veterinary applications such asto treat horses and livestock, e.g. cattle, sheep, cows, goats, swineand the like, and pets (companion animals) such as dogs and cats.

For diagnostic or research applications, a wide variety of mammals willbe suitable subjects including rodents (e.g. mice, rats, hamsters),rabbits, primates, and swine such as inbred pigs and the like.Additionally, for in vitro applications, such as in vitro diagnostic andresearch applications, body fluids (e.g. blood, plasma, serum, cellularinterstitial fluid, saliva, feces, and urine) and cell and tissuesamples of the above subjects will be suitable for use.

In an embodiment, the invention provides a method of treating a cancerdisorder in a patient identified as in need of such treatment, themethod comprising providing to the patient an effective amount of acompound of Formula I. The compounds and salts of Formula I providedherein may be administered alone, or in combination with one or moreother active agents.

In an embodiment, the method of treating cancer may additionallycomprise determining the cancer responds to Tdp2 inhibition.

In an embodiment, the method of treating cancer may additionallycomprise administering the compound of Formula I in combination with oneor more additional compounds, wherein at least one of the additionalcompounds is an active agent known to be an inhibitor of topoisomerase2, to a patient in need of such treatment.

In an embodiment, the method of treating cancer may additionallycomprise administering a therapeutically effective amount of a compoundor salt of Formula I, in combination with one or more additionalcompounds, wherein at least one additional compound is an active agentchosen from etoposide, teniposide, doxorubicin, daunorubicin,mitoxantrone, amsacrine, ellipticines, aurintricarboxylic acid, and3-hydroxy-2-[(1R)-6-isopropenyl-3-methyl-cyclohex-2-en-1-yl]-5-pentyl-1,4-benzoquinone(HU-331), to a patient in need of such treatment.

In other embodiments, the cancer is one which can be treated with Top2inhibitors, wherein TDP2 inhibitors may provide synergistic effects as acombination therapy with inhibitors of Top2, such as etoposide anddoxorubicin.

EXAMPLES Abbreviations

-   DCM Dichloromethane-   DMF N,N-Dimethylformamide-   DMSO Dimethyl Sulfoxide-   DTT Dithiothreitol-   EDTA Ethylenediaminetetraaceticacid-   ESI ElectrosprayIonization-   HPLC High Performance Liquid Chromatography-   HRMS High Resolution Mass Spectrometry-   NMR Nuclear Magnetic Resonance-   THF Tetrahydrofuran-   WCE Whole Cell Extract

General Methods

The reagents and solvents used were commercial anhydrous grade. Theywere used without further purification if not mentioned. Columnchromatography was carried out over silica gel (200-300 mesh). ¹H NMRspectra were recorded on a Bruker AVANCE III 400 MHz spectrometer usingtetramethylsilane as an internal reference. Mass spectra were analyzedon an Agilent 6120 (Quadrupole LCMS) mass spectrometer. Thehigh-resolution mass spectra were analyzed on a SHIMADZU LCMS-IT-TOFmass spectrometer. The HPLC analytical method employed a SHIMADZULC-20AB Liquid Chromatography system with SPD-M20A detector. Theanalytical method conditions included a Phenomenex C18 column (4.6×250mm, 5.0 um) and elution with a linear gradient of 25% methanol in pH 3.0buffered aqueous NaH₂PO₄ to 75% methanol at 1 mL/min flow rate. Thepurity was determined using UV peak area at 220 nm. HPLC method A used abuffer of H₂O with 0.1% TFA, method B used a buffer of phosphatebuffered saline at pH 6, method C used a buffer of phosphate bufferedsaline at pH 3.

EXAMPLES

The following scheme provides a general method for preparing compoundsof Formula I

Example 1. Synthesis of Compounds 1 and 2

To a yellow solution of 6,7-dichloroquinoline-5,8-dione (0.46 g, 2 mmol)in MeCN (30 ml), ethyl acetoacetate (0.26 ml, 2.2 mmol) and K₂CO₃ (1.10g, 8 mmol) were added. The resultant solution was stirred and refluxedfor 6 h. After completion of reaction, the reaction solution was cooledto room temperature, and concentrated under reduced pressure. The targetproducts were purified by silica gel column chromatography.

Ethyl 2-methyl-4,9-dioxo-4,9-dihydrofuro[3,2-g]quinoline-3-carboxylate(1), yellow solid. ¹H NMR (400 MHz, CDCl₃) δ 9.04 (d, J=4.8 Hz, 1H),8.54 (d, J=8.0 Hz, 1H), 7.67 (dd, J=7.6, 4.7 Hz, 1H), 4.46 (q, J=7.1 Hz,2H), 2.76 (s, 3H), 1.46 (t, J=6.7 Hz, 3H). HRMS (ESI) m/z: 284.0574[M−H]⁻, calcd for C₁₅H₁₀NO₅ 284.0564.

Ethyl 2-methyl-4,9-dioxo-4,9-dihydrofuro[2,3-g]quinoline-3-carboxylate(2), yellow solid. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (d, J=4.0 Hz, 1H),8.54 (d, J=7.6 Hz, 1H), 7.70 (dd, J=7.6, 4.7 Hz, 1H), 4.44 (q, J=6.7 Hz,2H), 2.76 (s, 3H), 1.48 (t, J=7.2 Hz, 3H). HRMS (ESI) m/z: 284.0551[M−H]⁻, calcd for C₁₅H₁₀NO₅ 284.0564.

Example 2. Synthesis of Compounds 8 and 9

According to Preparation 1, using acetylacetone as material to give thetarget products 8 and 9.

3-acetyl-2-methylfuro[3,2-g]quinoline-4,9-dione (8), yellow solid. ¹HNMR (400 MHz, CDCl₃) δ 9.07 (dd, J=4.7, 1.7 Hz, 1H), 8.54 (dd, J=7.9,1.7 Hz, 1H), 7.73 (dd, J=7.9, 4.7 Hz, 1H), 2.79 (s, 3H), 2.70 (s, 3H).HRMS (ESI) m/z: 256.0593 [M+H]+, calcd for C₁₄H₁₀NO₄ 256.0604.

3-acetyl-2-methylfuro[2,3-g]quinoline-4,9-dione (9), yellow solid. ¹HNMR (400 MHz, CDCl₃) δ 9.07 (d, J=4.5 Hz, 1H), 8.55 (dd, J=7.8, 1.2 Hz,1H), 7.73 (dd, J=7.8, 4.7 Hz, 1H), 2.81 (s, 3H), 2.70 (s, 3H)_(o) HRMS(ESI) m/z: 256.0613 [M+H]+, calcd for C₁₄H₁₀NO₄ 256.0604.

Example 3. Synthesis of Compound 3

According to Preparation 1, using 2,3-dichloronaphthalene-1,4-dione asmaterial to give the target product 3 (Ethyl2-methyl-4,9-dioxo-4,9-dihydronaphtho[2,3-b]furan-3-carboxylate), yellowsolid. ¹H NMR (400 MHz, CDCl₃) δ 8.23-8.16 (m, 2H), 7.76-7.74 (m, 2H),4.45 (q, J=7.1 Hz, 1H), 2.72 (s, 3H), 1.45 (t, J=7.1 Hz, 3H). HRMS (ESI)m/z: 307.0590 [M+Na]+, calcd for C₁₆H₁₂O₅Na 307.0577.

Example 4. Synthesis of Compounds 29 and 30

According to Preparation 1, using ethyl 3-oxo-3-phenylpropanoate asmaterial to give the target products 29 and 30.

Ethyl 4,9-dioxo-2-phenyl-4,9-dihydrofuro[3,2-g]quinoline-3-carboxylate(29), yellow solid. ¹H NMR (400 MHz, CDCl₃) δ 9.08 (dd, J=4.6, 1.6 Hz,1H), 8.53 (dd, J=7.9, 1.6 Hz, 1H), 8.21-7.84 (m, 2H), 7.72 (dd, J=7.9,4.7 Hz, 1H), 7.60-7.42 (m, 3H), 4.51 (q, J=7.1 Hz, 2H), 1.43 (t, J=7.1Hz, 3H). HRMS (ESI) m/z: 348.0865 [M+H]+, calcd for C₂₀H₁₄NO₅ 348.0866.

Ethyl 4,9-dioxo-2-phenyl-4,9-dihydrofuro[2,3-g]quinoline-3-carboxylate(30), yellow solid. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (dd, J=4.7, 1.7 Hz,1H), 8.58 (dd, J=7.9, 1.7 Hz, 1H), 8.00-7.95 (m, 2H), 7.72 (dd, J=7.9,4.7 Hz, 1H), 7.52-7.49 (m, 3H), 4.53 (q, J=7.1 Hz, 2H), 1.46 (t, J=7.1Hz, 3H). HRMS (ESI) m/z: 348.0887 [M+H]+, calcd for C₂₀H₁₄NO₅ 348.0866.

Example 5. Preparation 2: Synthesis of Compound 7

To the solution of 2 (1.10 g, 4 mmol) in MeOH or iso-propanol (300 ml),aqueous solution of K₂CO₃ (15%, 30 ml) was added. The reaction solutionwas refluxed for 12 h. The precipitate was filtered and dissolved inwater (500 ml). The aqueous solution was acidized to pH 3 withhydrochloric acid (2 N), and extracted with DCM (100 ml×3). The organicsolution was dried with anhydrous MgSO₄ and concentrated under reducedpressure. The resultant solid was recrystallized in MeOH to give thetarget compound yellow solid 7.

2-methyl-4,9-dioxo-4,9-dihydrofuro[2,3-g]quinoline-3-carboxylic acid(7). ¹H NMR (400 MHz, CDCl₃) δ 9.12 (dd, J=4.7, 1.7 Hz, 1H), 8.59 (dd,J=7.9, 1.7 Hz, 1H), 7.82 (dd, J=7.9, 4.7 Hz, 1H), 2.93 (s, 3H).

Example 6. Preparation 3: Synthesis of Compound 10

At room temperature, to a red solution of compound 7 (65 mg, 0.25 mmol)and triethylamine (0.07 ml, 0.5 mmol) in new distilled chloroform (20ml), thionyl chloride (1.25 ml) was added dropwise. The mixture wasstirred and refluxed for 5 h. The reaction solution was then cooled toroom temperature. The solvent was evaporated under reduced pressure. Theresidue was contained under reduced pressure for a period to get rid ofmost of the residual thionyl chloride to give an orange solid residue.The resultant residue was dissolved in new distilled chloroform (10 ml),and added dropwise to a solution of 4-(Dimethylamino)pyridine (35 mg,0.3 mmol) and ethanediol (0.3 mmol) in new distilled chloroform (30 ml).The reaction mixture was refluxed for 3 h, and cooled to roomtemperature. The solvent was evaporated under reduced pressure. Thetarget product was purified by silica gel column chromatography.

2-hydroxyethyl-2-methyl-4,9-dioxo-4,9-dihydrofuro[2,3-g]quinoline-3-carboxylate(10), yellow solid. ¹H NMR (400 MHz, CDCl₃) δ 9.08 (d, J=3.2 Hz, 1H),8.56 (d, J=7.6 Hz, 1H), 7.73 (dd, J=7.4, 4.4 Hz, 1H), 4.49 (t, J=4.4 Hz,2H), 4.00 (t, J=4.4 Hz, 2H), 2.80 (s, 3H). HRMS (ESI) m/z: 300.0499[M−H]⁻, calcd for C₁₅H₁₀NO₆ 300.0514.

Example 7. Synthesis of Compound 11

According to Preparation 3, using propanediol as material to give thetarget yellow solid 11. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (d, J=3.3 Hz,1H), 8.54 (d, J=7.0 Hz, 1H), 7.71 (dd, J=7.6, 4.7 Hz, 1H), 4.55 (t,J=5.9 Hz, 2H), 3.91 (t, J=5.9 Hz, 2H), 2.77 (s, 3H), 2.09 (quint, J=5.8Hz, 2H). HRMS (ESI) m/z: 314.0653 [M−H]⁻, calcd for C₁₆H₁₂NO₆ 314.0670.

Example 8 Synthesis of Compound 12

According to Preparation 3, using m-dihydroxybenzene as material to givethe target yellow solid 12. ¹H NMR (400 MHz, DMSO) δ 9.81 (s, 1H), 9.03(d, J=3.1 Hz, 1H), 8.49 (d, J=7.2 Hz, 1H), 7.87 (dd, J=6.6, 4.9 Hz, 1H),7.31-7.26 (m, 1H), 6.88-6.68 (m, 3H), 2.76 (s, 3H). HRMS (ESI) m/z:348.0499 [M−H]⁻, calcd for C₁₉H₁₀NO₆ 348.0514.

Example 9. Synthesis of Compound 13

According to Preparation 3, using o-dihydroxybenzene as material to givethe target yellow solid 13. ¹H NMR (400 MHz, DMSO) δ 9.81 (s, 1H), 9.03(d, J=3.9 Hz, 1H), 8.49 (d, J=7.7 Hz, 1H), 7.87 (dd, J=7.6, 4.7 Hz, 1H),7.23 (d, J=7.8 Hz, 1H), 7.16 (t, J=7.6 Hz, 1H), 7.00 (d, J=7.9 Hz, 1H),6.90 (t, J=7.5 Hz, 1H), 2.80 (s, 3H). HRMS (ESI) m/z: C₁₉H₁₀NO₆ 348.0514[M−H]⁻, calcd for 348.0512.

Example 10. Synthesis of Compound 14

According to Preparation 3, using phenol as material to give the targetyellow solid 14. ¹H NMR (400 MHz, DMSO) δ 9.03 (dd, J=4.7, 1.7 Hz, 1H),8.49 (dd, J=7.9, 1.7 Hz, 1H), 7.87 (dd, J=7.9, 4.7 Hz, 1H), 7.62-7.46(m, 2H), 7.44-7.29 (m, 3H), 2.78 (s, 3H). HRMS (ESI) m/z: 332.0563[M−H]⁻, calcd for C₁₉H₁₀NO₅ 332.0564.

Example 11. Synthesis of Compound 15

According to Preparation 3, using phenol as material to give the targetyellow solid 15. ¹H NMR (400 MHz, CDCl₃) δ 9.08 (dd, J=4.7, 1.7 Hz, 1H),8.55 (dd, J=7.9, 1.7 Hz, 1H), 7.73 (dd, J=7.9, 4.7 Hz, 1H), 4.47 (d,J=5.2 Hz, 2H), 4.19-4.17 (m, 1H), 3.83-3.74 (m, 2H), 2.80 (s, 3H). HRMS(ESI) m/z: 330.0604 [M−H]⁻, calcd for C₁₆H₁₂NO₇ 330.0619.

Example 12. Synthesis of Compound 16

According to Preparation 3, using phenylamine as material to give thetarget yellow solid 16. ¹H NMR (400 MHz, DMSO) δ 11.10 (s, 1H), 9.06 (d,J=3.2 Hz, 1H), 8.51 (dd, J=7.8, 1.5 Hz, 1H), 7.91 (dd, J=7.7, 4.7 Hz,1H), 7.77-7.75 (m, 2H), 7.44-7.40 (m, 2H), 7.18-7.14 (m, 1H), 2.78 (s,3H). HRMS (ESI) m/z: 331.0723 [M−H]⁻, calcd for C₁₉H₁₁N₂O₄ 331.0724.

Example 13. Synthesis of Compound 17

According to Preparation 3, using m-chlorophenylamine as material togive the target yellow solid 17. ¹H NMR (400 MHz, DMSO) δ 11.19 (s, 1H),9.07 (d, J=3.2 Hz, 1H), 8.51 (dd, J=7.8, 1.5 Hz, 1H), 7.96 (s, 1H), 7.92(dd, J=7.7, 4.7 Hz, 1H), 7.59 (d, J=8.2 Hz, 1H), 7.45 (t, J=8.1 Hz, 1H),7.23 (d, J=7.8 Hz, 1H), 2.76 (s, 3H). HRMS (ESI) m/z: 367.0501 [M+H]⁺,calcd for C₁₉H₁₂N₂O₄Cl 367.0480.

Example 14. Synthesis of Compound 18

According to Preparation 3, using o-aminophenol as material to give thetarget yellow solid 18. ¹H NMR (400 MHz, DMSO) δ 11.11 (s, 1H), 10.02(s, 1H), 9.05 (d, J=3.3 Hz, 1H), 8.49 (d, J=6.7 Hz, 1H), 8.18 (d, J=7.8Hz, 1H), 7.90 (dd, J=7.7, 4.7 Hz, 1H), 7.01-6.93 (m, 2H), 6.82 (t, J=7.3Hz, 1H), 2.83 (s, 3H). HRMS (ESI) m/z: 347.0656 [M−H]⁻, calcd forC₁₉H₁₁N₂O₅ 347.0673.

Example 15. Synthesis of Compound 19

According to Preparation 3, using p-methoxyphenylamine as material togive the target red solid 19. ¹H NMR (400 MHz, DMSO) δ 11.00 (s, 1H),9.07 (d, J=3.3 Hz, 1H), 8.50 (dd, J=7.8, 1.6 Hz, 1H), 7.91 (dd, J=7.7,4.7 Hz, 1H), 7.67 (d, J=9.0 Hz, 2H), 6.99 (d, J=9.0 Hz, 2H), 3.77 (s,3H), 2.77 (s, 3H). HRMS (ESI) m/z: 361.0817 [M−H]⁻, calcd for C₂₀H₁₃N₂O₅361.0830.

Example 16. Synthesis of Compound 20

According to Preparation 3, using ethylamine as material to give thetarget yellow solid 20. ¹H NMR (400 MHz, CDCl₃) δ 9.52 (s, 1H), 9.08 (d,J=3.3 Hz, 1H), 8.56 (d, J=7.4 Hz, 1H), 7.76 (dd, J=7.7, 4.7 Hz, 1H),3.50 (q, J=6.5 Hz, 2H), 2.93 (s, 3H), 1.34 (t, J=7.2 Hz, 3H). HRMS (ESI)m/z: 307.0699 [M+Na]⁺, calcd for C₁₅H₁₂N₂O₄Na 307.0689.

Example 17. Synthesis of Compound 22

According to Preparation 3, using dimethyl 2-hydroxyethylphosphonate asmaterial to give the target yellow solid 22. ¹H NMR (400 MHz, CDCl₃) δ9.06 (dd, J=4.6, 1.6 Hz, 1H), 8.54 (dd, J=7.9, 1.6 Hz, 1H), 7.71 (dd,J=7.9, 4.7 Hz, 1H), 4.64-4.58 (m, 2H), 3.80 (s, 3H), 3.77 (s, 3H), 2.77(s, 3H), 2.54-2.39 (m, 2H). HRMS (ESI) m/z: 392.0538 [M−H]⁻, calcd forC₁₇H₁₅NO₈P 392.0541.

Example 18. Synthesis of Compound 23

According to Preparation 3, using m-chlorophenol as material to give thetarget yellow solid 23. ¹H NMR (400 MHz, CDCl₃) δ 9.07 (dd, J=4.6, 1.6Hz, 1H), 8.56 (dd, J=7.9, 1.6 Hz, 1H), 7.72 (dd, J=7.9, 4.7 Hz, 1H),7.52 (s, 1H), 7.39-7.35 (m, 2H), 7.30-7.26 (m, 1H), 2.83 (s, 1H). HRMS(ESI) m/z: 368.0341 [M+H]⁺, calcd for C₁₉H₁₁NO₅Cl 368.0320.

Example 19. Synthesis of Compound 24

According to Preparation 3, using o-chlorophenol as material to give thetarget yellow solid 24. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (dd, J=4.6, 1.6Hz, 1H), 8.56 (dd, J=7.9, 1.7 Hz, 1H), 7.72 (dd, J=7.9, 4.7 Hz, 1H),7.53-7.49 (m, 2H), 7.38 (td, J=7.8, 1.5 Hz, 1H), 7.29-7.25 (m, 1H), 2.85(s, 3H). HRMS (ESI) m/z: 368.0335 [M+H]⁺, calcd for C₁₉H₁₀NO₅Cl368.0320.

Example 20. Synthesis of Compound 25

According to Preparation 3, using 2-naphthalenol as material to give thetarget yellow solid 25. ¹H NMR (400 MHz, CDCl₃) δ 9.07 (d, J=4.6 Hz,1H), 8.56 (d, J=7.8 Hz, 1H), 7.94-9.86 (m, 4H), 7.72 (dd, J=7.9, 4.6 Hz,1H), 7.60 (dd, J=8.8, 2.2 Hz, 1H), 7.55-7.41 (m, 2H), 2.86 (s, 3H). HRMS(ESI) m/z: 382.0706 [M−H]⁻, calcd for C₂₃H₁₂NO₅ 382.0721.

Example 21. Synthesis of Compound 26

According to Preparation 3, using 3-hydroxybenzonitrile as material togive the target yellow solid 26. ¹H NMR (400 MHz, CDCl₃) δ 9.08 (dd,J=4.7, 1.7 Hz, 1H), 8.57 (dd, J=7.9, 1.7 Hz, 1H), 7.82 (s, 1H),7.79-7.75 (m, 1H), 7.74 (dd, J=7.9, 4.7 Hz, 1H), 7.66-7.48 (m, 2H), 2.84(s, 3H). HRMS (ESI) m/z: 359.0679 [M+H]⁺, calcd for C₂₀H₁₁N₂O₅ 359.0662.

Example 22. Synthesis of Compound 27

According to Preparation 3, using p-chlorophenol as material to give thetarget yellow solid 27. ¹H NMR (400 MHz, CDCl₃) δ 9.07 (dd, J=4.6, 1.6Hz, 1H), 8.56 (dd, J=7.9, 1.6 Hz, 1H), 7.72 (dd, J=7.9, 4.7 Hz, 1H),7.41 (br, s, 4H), 2.82 (s, 3H). HRMS (ESI) m/z: 368.0334 [M+H]⁺, calcdfor C₁₉H₁₁NO₅Cl 368.0320.

Example 23. Synthesis of Compound 28

According to Preparation 3, using 3-hydroxyl pyridine as material togive the target yellow solid 28. ¹H NMR (400 MHz, CDCl₃) δ 9.08 (dd,J=4.7, 1.7 Hz, 1H), 8.77 (d, J=2.5 Hz, 1H), 8.58-8.55 (m, 2H), 7.87(ddd, J=8.3, 2.7, 1.4 Hz, 1H), 7.73 (dd, J=7.9, 4.7 Hz, 1H), 7.43 (dd,J=8.3, 4.8 Hz, 1H), 2.85 (s, 3H). HRMS (ESI) m/z: 335.0673 [M+H], calcdfor C₁₈H₁₁N₂O₅ 335.0662.

Example 24. Synthesis of Compound 31

According to Preparation 3, using 4-bromophenol as material to give thetarget yellow solid 31. ¹H NMR (400 MHz, CDCl₃) δ 9.07 (dd, J=4.7, 1.7Hz, 1H), 8.56 (dd, J=7.9, 1.7 Hz, 1H), 7.72 (dd, J=7.9, 4.7 Hz, 1H),7.56 (d, J=8.8 Hz, 2H), 7.36 (d, J=8.8 Hz, 2H), 2.82 (s, 3H). HRMS (ESI)m/z: 411.9820 and 413.9865 [M+H]⁺, calcd for C₁₉H₁₁NO₅ Br 411.9815 and413.9797.

Example 25. Synthesis of Compound 32

According to Preparation 3, using 3-ethynylphenol as material to givethe target yellow solid 32. ¹H NMR (400 MHz, CDCl₃) δ 9.07 (dd, J=4.6,1.5 Hz, 1H), 8.56 (dd, J=7.9, 1.7 Hz, 1H), 7.72 (dd, J=7.9, 4.7 Hz, 1H),7.60 (s, 1H), 7.50-7.34 (m, 3H), 3.12 (s, 1H), 2.83 (s, 3H). HRMS (ESI)m/z: 380.0543 [M+Na]⁺, calcd for C₂₁H₁₁NO₅Na 380.0529.

Example 26. Synthesis of Compound 35

According to Preparation 3, using butane-1,4-diol as material to givethe target yellow solid 35. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (d, J=3.5 Hz,1H), 8.54 (dd, J=7.8, 1.1 Hz, 1H), 7.71 (dd, J=7.8, 4.6 Hz, 1H), 4.43(t, J=6.4 Hz, 2H), 3.75 (t, J=6.3 Hz, 2H), 2.76 (s, 3H), 2.00-1.92 (m,2H), 1.85-1.78 (m, 2H). HRMS (ESI) m/z: 352.0810 [M+Na]⁺, calcd forC₁₇H₁₅NO₆Na 352.0792.

Example 27. Synthesis of Compound 36

According to Preparation 3, using 2,2′-oxydiethanol as material to givethe target yellow solid 36. ¹H NMR (400 MHz, CDCl₃) δ 9.05 (dd, J=4.7,1.7 Hz, 1H), 8.53 (dd, J=7.9, 1.7 Hz, 1H), 7.71 (dd, J=7.9, 4.7 Hz, 1H),4.54 (t, J=4.6 Hz, 2H), 3.93 (t, J=4.8 Hz, 2H), 3.79 (t, J=4.4 Hz, 2H),3.70 (t, J=4.4 Hz, 2H), 2.76 (s, 3H). HRMS (ESI) m/z: 368.0752 [M+Na]⁺,calcd for C₁₇H₁₅NO₇Na 368.0741.

Example 28. Synthesis of Compound 37

According to Preparation 3, using(R)-(2,2-dimethyl-1,3-dioxolan-4-yl)methanol as material to give thetarget yellow solid 37. ¹H NMR (400 MHz, CDCl₃) δ 9.09 (dd, J=4.6, 1.6Hz, 1H), 8.57 (dd, J=7.8, 1.5 Hz, 1H), 7.75 (dd, J=7.8, 4.7 Hz, 1H),4.48 (d, J=4.7 Hz, 2H), 4.19 (m, 1H), 3.85-3.76 (m, 2H), 2.81 (s, 3H).

Example 29. Synthesis of Compounds 38 and 45

According to Preparation 3, using(S)-(2,2-dimethyl-1,3-dioxolan-4-yl)methanol as material to give twoyellow solids, 38 and 45.

38: ¹H NMR (400 MHz, CDCl₃) δ 8.99 (dd, J=4.7, 1.7 Hz, 1H), 8.47 (dd,J=7.9, 1.7 Hz, 1H), 7.64 (dd, J=7.9, 4.7 Hz, 1H), 4.54-4.46 (m, 1H),4.36 (dd, J=11.0, 5.4 Hz, 1H), 4.30 (dd, J=11.0, 6.5 Hz, 1H), 4.19 (dd,J=8.7, 6.3 Hz, 1H), 3.94 (dd, J=8.7, 5.4 Hz, 1H), 2.70 (s, 3H), 1.37 (s,3H), 1.31 (s, 3H). HRMS (ESI) m/z: 394.0909 [M+Na]⁺, calcd forC₁₉H₁₇NO₇Na 394.0897.

45: ¹H NMR (400 MHz, CDCl₃) δ 9.01 (dd, J=4.7, 1.7 Hz, 1H), 8.48 (dd,J=7.9, 1.7 Hz, 1H), 7.66 (dd, J=7.9, 4.7 Hz, 1H), 4.40 (d, J=5.2 Hz,2H), 4.14-4.08 (m, 1H), 3.76-3.63 (m, 2H), 2.73 (s, 3H). HRMS (ESI) m/z:354.0596 [M+Na]⁺, calcd for C₁₆H₁₃NO₇Na 354.0584.

Example 30. Synthesis of Compound 39

According to Preparation 3, using phenylmethanol as material to give thetarget yellow solid 39. ¹H NMR (400 MHz, CDCl3) δ 9.06 (dd, J=4.6, 1.6Hz, 1H), 8.53 (dd, J=7.9, 1.6 Hz, 1H), 7.69 (dd, J=7.8, 4.7 Hz, 1H),7.58-7.56 (m, 2H), 7.42-7.37 (m, 2H), 7.35-7.31 (m, 1H), 5.42 (s, 2H),2.73 (s, 3H). HRMS (ESI) m/z: 370.0704 [M+Na]⁺, calcd for C₂₀H₁₃NO₅Na370.0686.

Example 31. Synthesis of Compound 40

According to Preparation 3, using 2-phenylethanol as material to givethe target yellow solid 40. ¹H NMR (400 MHz, CDCl₃) δ 9.07 (dd, J=4.7,1.7 Hz, 1H), 8.54 (dd, J=7.9, 1.7 Hz, 1H), 7.70 (dd, J=7.9, 4.7 Hz, 1H),7.33-7.28 (m, 4H), 7.25-7.20 (m, 1H), 4.60 (t, J=7.3 Hz, 2H), 3.19 (t,J=7.3 Hz, 2H), 2.65 (s, 3H). HRMS (ESI) m/z: 384.0864 [M+Na]⁺, calcd forC₂₁H₁₅NO₅Na 384.0842.

Example 32. Synthesis of Compound 58

According to Preparation 3, using pentane-1,5-diol as material to givethe target yellow solid 45. ¹H NMR (400 MHz, CDCl₃) δ 9.05 (dd, J=4.7,1.7 Hz, 1H), 8.53 (dd, J=7.9, 1.7 Hz, 1H), 7.70 (dd, J=7.9, 4.7 Hz, 1H),4.40 (t, J=6.5 Hz, 2H), 3.71 (t, J=6.1 Hz, 2H), 2.76 (s, 3H), 1.93-1.85(m, 2H), 1.73-1.55 (m, 4H). HRMS (ESI) m/z: 366.0966 [M+Na]⁺, calcd forC₁₈H₁₇NO₆Na 366.0948.

Example 33. Synthesis of Compound 46

According to Preparation 3, using 2-hydroxyl acetic acid as material togive the target yellow solid 46. ¹H NMR (400 MHz, MeOD) δ 8.95 (dd,J=4.7, 1.6 Hz, 1H), 8.58 (dd, J=7.9, 1.6 Hz, 1H), 7.84 (dd, J=7.9, 4.8Hz, 1H), 4.07 (s, 2H), 2.78 (s, 3H). HRMS (ESI) m/z: 338.0283 [M+Na]⁺,calcd for C₁₅H₉NO₇Na 338.0271.

Example 34. Synthesis of Compound 47

According to Preparation 3, using trifloroethanol as material to givethe target yellow solid 47. ¹H NMR (400 MHz, CDCl₃) δ 9.07 (dd, J=4.7,1.7 Hz, 1H), 8.54 (dd, J=7.9, 1.7 Hz, 1H), 7.71 (dd, J=7.9, 4.7 Hz, 1H),4.77 (q, J=8.3 Hz, 2H), 2.78 (s, 3H). HRMS (ESI) m/z: 362.0266 [M+Na]⁺,calcd for C₁₅H₈NO₅F₃Na 362.0247.

Example 35. Synthesis of Compound 48

According to Preparation 3, using 3-hydroxypropanenitrile as material togive the target yellow solid 48. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (dd,J=4.6, 1.6 Hz, 1H), 8.54 (dd, J=7.9, 1.7 Hz, 1H), 7.72 (dd, J=7.9, 4.7Hz, 1H), 4.60 (t, J=6.5 Hz, 2H), 2.99 (t, J=6.5 Hz, 2H), 2.78 (s, 3H).

Example 36. Synthesis of Compound 49

According to Preparation 3, using benzo[d][1,3]dioxol-5-ol as materialto give the target yellow solid 49. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (dd,J=4.7, 1.7 Hz, 1H), 8.55 (dd, J=7.9, 1.7 Hz, 1H), 7.72 (dd, J=7.9, 4.7Hz, 1H), 6.97 (d, J=2.3 Hz, 1H), 6.89 (dd, J=8.4, 2.3 Hz, 1H), 6.82 (d,J=8.4 Hz, 1H), 6.01 (s, 2H), 2.81 (s, 2H).

Example 37. Synthesis of Compound 43

According to Preparation 3, using prop-2-yn-1-ol as material to give thetarget yellow solid 43. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (d, J=4.5 Hz,1H), 8.54 (d, J=7.7 Hz, 1H), 7.70 (dd, J=7.8, 4.6 Hz, 1H), 4.50 (t,J=7.0 Hz, 2H), 2.88-2.64 (m, 5H), 2.02 (t, J=2.6 Hz, 1H). HRMS (ESI)m/z: 332.0544 [M+Na]⁺, calcd for C₁₇H₁₁NO₅Na 332.0529.

Example 38. Synthesis of Compound 44

According to Preparation 3, using 4-(methylsulfonyl)phenol as materialto give the target yellow solid 44. ¹H NMR (400 MHz, CDCl₃) δ 9.10 (dd,J=4.7, 1.7 Hz, 1H), 8.59 (dd, J=7.9, 1.7 Hz, 1H), 8.11-8.03 (m, 2H),7.76 (dd, J=7.9, 4.7 Hz, 1H), 7.76-7.63 (m, 2H), 3.11 (s, 3H), 2.86 (s,3H). HRMS (ESI) m/z: 434.0334 [M+H]⁺, calcd for C₂₀H₁₃NO₇SNa 434.0305.

Example 39. Synthesis of Compound 50

According to Preparation 3, using 2-hydroxybenzonitrile as material togive the target yellow solid 50. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (dd,J=4.7, 1.7 Hz, 1H), 8.57 (dd, J=7.9, 1.7 Hz, 1H), 7.92-7.61 (m, 4H),7.42 (td, J=7.5, 1.4 Hz, 1H), 2.87 (s, 3H). HRMS (ESI) m/z: 381.0503[M+Na]⁺, calcd for C₂₀H₁₀N₂O₅Na 381.0482.

Example 40. Synthesis of Compound 51

According to Preparation 3, using 4-hydroxybenzonitrile as material togive the target yellow solid 51. ¹H NMR (400 MHz, CDCl₃) δ 9.08 (dd,J=4.7, 1.7 Hz, 1H), 8.57 (dd, J=7.9, 1.7 Hz, 1H), 7.76 (d, J=8.8 Hz,1H), 7.74 (dd, J=7.0, 3.7 Hz, 2H), 7.63 (d, J=8.8 Hz, 2H), 2.84 (s, 3H).HRMS (ESI) m/z: 381.0496 [M+Na]⁺, calcd for C₂₀H₁₀N₂O₅Na 381.0482.

Example 41. Synthesis of Compound 52

According to Preparation 3, using N-acetyl-L-tyrosine methyl ester asmaterial to give the target yellow solid 52. ¹H NMR (400 MHz, CDCl₃) δ9.06 (dd, J=4.7, 1.7 Hz, 1H), 8.56 (dd, J=7.9, 1.7 Hz, 1H), 7.72 (dd,J=7.9, 4.7 Hz, 1H), 7.38 (d, J=8.5 Hz, 2H), 7.17 (d, J=8.5 Hz, 2H), 5.98(d, J=7.5 Hz, 1H), 4.91 (dt, J=7.7, 5.7 Hz, 1H), 3.75 (s, 3H), 3.17 (dd,J=5.6, 3.4 Hz, 2H), 2.82 (s, 3H), 2.02 (s, 3H). ESI/MS m/z: 477.1 [M+H].

Example 42. Synthesis of Compounds 53 and 54

According to Preparation 3, using 3-bromopropanol as material to givethe target yellow solid 53. ¹H NMR (400 MHz, CDCl₃) δ 9.06 (dd, J=4.7,1.7 Hz, 1H), 8.54 (dd, J=7.9, 1.7 Hz, 1H), 7.70 (dd, J=7.9, 4.7 Hz, 1H),4.54 (t, J=5.8 Hz, 2H), 3.75 (t, J=5.4 Hz, 2H), 2.78 (s, 3H), 2.45-2.36(m, 2H). HRMS (ESI) m/z: 377.9996 and 380.0005 [M+H]⁺, calcd forC₁₆H₁₂NO₅Br 377.9972 and 379.9953.

The solution of 53 (20 mg, 0.05 mmol) in pyridine (5 ml) was heatedunder 80 for 8 h. And then, the reaction solution was cooled to roomtemperature, and added with ether (5 ml). The precipitate was filtered,and washed with ether (10 ml) and ethyl acetate (5 ml), respectively, togive the target yellow solid 54. ¹H NMR (400 MHz, MeOD) δ 9.20 (d, J=5.6Hz, 2H), 9.02 (dd, J=4.7, 1.6 Hz, 1H), 8.64-8.60 (m, 2H), 8.18 (t, J=7.2Hz, 2H), 7.89 (dd, J=7.9, 4.8 Hz, 1H), 5.08 (t, J=7.4 Hz, 2H), 4.46 (t,J=5.6 Hz, 2H), 2.74 (s, 3H), 2.64-2.48 (m, 2H). HRMS (ESI) m/z: 377.1149[M−Br]⁺, calcd for C₂₁H₁₇N₂O₅ 377.1132.

Example 43. Synthesis of Compound 55

The solution of 53 (20 mg, 0.05 mmol) and N,N-dimethyl-4-aminopyridine(62 mg, 0.5 mmol) in THF (10 ml) was refluxed for 8 h. And then, thereaction solution was cooled to room temperature, and added with ether(20 ml). The precipitate was filtered, and washed with ether (10 ml) andethyl acetate (5 ml), respectively, to give the target yellow solid 55.¹H NMR (400 MHz, MeOD) δ 9.01 (dd, J=4.7, 1.5 Hz, 1H), 8.61 (dd, J=7.9,1.5 Hz, 1H), 8.35 (d, J=7.7 Hz, 2H), 7.89 (dd, J=7.9, 4.8 Hz, 1H), 7.01(d, J=7.7 Hz, 2H), 4.57 (t, J=7.0 Hz, 2H), 4.40 (t, J=5.6 Hz, 2H), 3.21(s, 6H), 2.74 (s, 3H), 2.45-2.31 (m, 2H). HRMS (ESI) m/z: 420.1555[M−Br]⁺, calcd for C₂₃H₂₂N₃O₅ 420.1554.

Example 44. Preparation 4: Synthesis of Compound 33

To the solution of 3-bromopropanoic acid (152 mg, 1 mmol) in MeCN (20ml), NaN₃ (130 mg, 2 mmol) was added. The solution was refluxed for 8 h.The reaction solution was concentrated under reduced pressure to givewhite solid. The resultant white solid was dissolved in water (5 ml),and was added with compound 32 (60 mg, 0.17 mmol), CuSO₄ (3 mg), sodiumascorbate (2.5 mg) and DMF (5 ml), respectively. The solution was heatedto 80° C. for 3 h. And then, the reaction solution was cooled to roomtemperature, and added with water (50 ml). The resultant suspension wasextracted with CH₂Cl₂ (20 ml×2). The combined organic solution waswashed with water (10 ml×3) and saturated saline solution (10 ml×2). Theorganic solution was concentrated under reduced pressure and purified bysilica gel column chromatography to give the target yellow solid 33. ¹HNMR (400 MHz, DMSO) δ 12.54 (s, 1H), 9.04 (dd, J=4.6, 1.6 Hz, 1H), 8.68(s, 1H), 8.50 (dd, J=7.9, 1.6 Hz, 1H), 7.89 (dd, J=7.9, 4.7 Hz, 1H),7.85 (d, J=1.9 Hz, 1H), 7.82 (d, J=7.8 Hz, 1H), 7.60 (t, J=7.9 Hz, 1H),7.35 (dd, J=8.1, 1.4 Hz, 1H), 4.63 (t, J=6.7 Hz, 2H), 2.97 (t, J=6.7 Hz,2H), 2.81 (s, 3H). HRMS (ESI) m/z: 471.0920 [M−H]⁻, calcd for C₂₄H₁₅N₄O₇471.0946.

Example 45. Synthesis of Compound 34

According to Preparation 4, using 3-bromopropanol as material to givethe target yellow solid 34. ¹H NMR (400 MHz, CDCl₃) δ 9.08 (dd, J=4.7,1.7 Hz, 1H), 8.58 (dd, J=7.9, 1.7 Hz, 1H), 7.93 (s, 1H), 7.85-7.82 (m,2H), 7.74 (dd, J=7.9, 4.7 Hz, 1H), 7.52 (t, J=7.9 Hz, 1H), 7.44-7.37 (m,1H), 4.61 (t, J=6.7 Hz, 2H), 3.72 (t, J=5.8 Hz, 2H), 2.85 (s, 3H), 2.21(quint, J=6.2 Hz, 2H). HRMS (ESI) m/z: 457.1138 [M−H]⁻, calcd forC₂₄H₁₇N₄O₆ 457.1154.

Example 46. Synthesis of Compound 42

According to Preparation 4, using compound 43 as material to give thetarget yellow solid 42. ¹H NMR (400 MHz, CDCl₃) δ 8.99 (dd, J=4.8, 1.4Hz, 1H), 8.65 (dd, J=7.9, 1.5 Hz, 1H), 8.19 (s, 1H), 7.83 (dd, J=7.9,4.8 Hz, 1H), 4.78 (t, J=5.6 Hz, 2H), 4.70 (t, J=5.0 Hz, 2H), 3.24 (t,J=5.0 Hz, 2H), 2.92 (t, J=5.6 Hz, 2H), 2.79 (s, 2H). HRMS (ESI) m/z:423.0923 [M−H]⁻, calcd for C₂₀H₁₅N₄O₇ 423.0946.

Example 47. Synthesis of Compound 56

According to Synthesis of 42, using 3-bromopropanol as material to givethe target yellow solid 56. ¹H NMR (400 MHz, CDCl₃) δ 9.02 (d, J=4.5 Hz,1H), 8.57 (dd, J=7.9, 1.6 Hz, 1H), 7.98 (s, 1H), 7.75 (dd, J=7.9, 4.7Hz, 1H), 4.70 (t, J=5.6 Hz, 2H), 4.58 (t, J=5.6 Hz, 2H), 3.68 (t, J=5.8Hz, 2H), 3.27 (t, J=5.6 Hz, 2H), 2.76 (s, 3H), 2.15 (quint, J=6 Hz, 2H).HRMS (ESI) m/z: 433.1142 [M+Na]⁺, calcd for C₂₀H₁₈N₄O₆Na 433.1119.

Example 48. Synthesis of Compound 7-Na Salt

To a solution of 7 (52 mg, 0.20 mmol) in ethanol (10 ml), a solution ofNaOH (8 mg, 0.2 mmol) in ethanol (5 ml) was added dropwish. The solutionwas stirred at room temperature for 30 min. The precipitate wasfiltered, washed with ethanol (1 ml×2) and dried to give the targetyellow solid 7-Na salt.

Example 49. Synthesis of Compound 33-Na Salt

According to Synthesis of 7-Na salt, using compound 33 as material togive the target yellow solid 33-Na salt.

Example 50. Synthesis of Compound 57

The solution of 2 (72 mg, 0.25 mmol), hydroxylamine hydrochloride (52mg, 0.75 mmol) and K₂CO₃ (52 mg, 0.375 mmol) in ethanol (10 ml) wasstirred and refluxed for 1.5 h. The reaction solution was concentrationunder reduced pressure. The resultant solid was purified by silica gelcolumn chromatography to give the target yellow solid 57. ¹H NMR (400MHz, CDCl₃) δ 8.76-8.74 (m, 2H), 7.76 (dd, J=8.0, 5.0 Hz, 1H), 4.42 (q,J=7.1 Hz, 2H), 2.64 (s, 3H), 1.41 (t, J=7.1 Hz, 3H).

Example 51. Additional Compounds

The following compounds can be prepared by the methods shown in Examples1-50. Routine changes in reagents and reaction conditions needed to makethe particular compounds will be apparent to those of skill in the art.

Example 52. Whole Cell Extract Tdp1 Assay

DT40 knockout cells (1×10⁷) for Tdp1 (TDP1−/−) complemented with humanTDP1 (hTDP1) were collected, washed, and centrifuged. Cell pellets werethen resuspended in 100 μL of CellLytic M cell lysis reagent(SIGMA-Aldrich C2978). After 15 min on ice, lysates were centrifuged at12,000 g for 10 min, and supernatants were transferred to a new tube.Protein concentrations were determined using a Nanodropspectrophotometer (Invitrogen), and whole cell extracts were stored at−80° C. A 5′-[³²P]-labeled single-stranded DNA oligonucleotidecontaining a 3′-phosphotyrosine (N14Y) was incubated at 1 nM with 4μg/mL of whole cell extracts in the absence or presence of inhibitor for15 min at room temperature in the WCE buffer containing 50 mM Tris HCl,pH 7.5, 80 mM KCl, 2 mM EDTA, 1 mM DTT, 40 μg/mL BSA, and 0.01%Tween-20. Reactions were terminated by the addition of 1 volume of gelloading buffer [99.5% (v/v) formamide, 5 mM EDTA, 0.01% (w/v) xylenecyanol, and 0.01% (w/v) bromophenol blue]. Samples were subjected to a16% denaturing PAGE with multiple loadings at 12-min intervals. Gelswere dried and exposed to a PhosphorImager screen (GE Healthcare). Gelimages were scanned using a Typhoon 8600 (GE Healthcare), anddensitometry analyses were performed using the ImageQuant software (GEHealthcare).

Example 53. Recombinant Tdp1 Assay

The N14Y DNA substrate was incubated at 1 nM with 10 pM recombinant TDP1in the absence or presence of inhibitor for 15 min at room temperaturein WCE buffer (see Example 51). When indicated, parallel reactions wereperformed in the HTS assay buffer containing 1×PBS, pH 7.4, 80 mM KCl,and 0.01% Tween-20. Samples were then analyzed similarly to the WCE TDP1assay (Example 51).

Example 54. Recombinant Tdp2 Assay

TDP2 reactions were carried out as described previously (Example 52)with the following modifications. The 18-mer single-strandedoligonucleotide DNA substrate (α³²P-cordycepin-3′-labeled) was incubatedat 1 nM with 25 pM recombinant human TDP2 in the absence or presence ofinhibitor for 15 min at room temperature in a buffer containing 50 mMTris-HCl, pH 7.5, 80 mM KCl, 5 mM MgCl₂, 0.1 mM EDTA, 1 mM DTT, 40 μg/mLBSA, and 0.01% Tween 20. Reactions were terminated and treated similarlyto WCE and recombinant TDP1 reactions (see Examples 52 and 53).

Example 55. Whole Cell Extract Tdp2 Assay

DT40 knockout cells (1×10⁷) for Tdp1 (TDP1−/−) complemented with humanTDP2 (hTDP2) were collected, washed, and centrifuged. Cell pellets werethen lysed and stored similarly to hTDP1 extracts (see above). The18-mer single-stranded oligonucleotide was incubated at 1 nM with 4μg/mL of whole cell extracts in the absence or presence of inhibitor for15 min at room temperature in the WCE buffer containing 50 mM Tris HCl,pH 7.5, 80 mM KCl, 5 mM MgCl₂, 2 mM EDTA, 1 mM DTT, 40 μg/mL BSA, and0.01% Tween-20. Reactions were terminated by the addition of 1 volume ofgel loading buffer [99.5% (v/v) formamide, 5 mM EDTA, 0.01% (w/v) xylenecyanol, and 0.01% (w/v) bromophenol blue]. Samples were then treated andrun similarly to the hTDP1 whole cell extract (Example 51).

Example 56. Additional Compounds

Table 1 shows compounds of compounds 1 to 44 and additional compounds59-74. All compounds were prepared by the methods shown in Examples 1 to50. Routine changes in starting materials and reaction conditions,readily apparent to those of skill in the art, were used to make theparticular compounds disclosed in Table 1. 4 stars “****” is used todenote compounds with an IC₅₀≤1 micromolar, 3 stars “***” indicates acompound with 1 micromolar <IC₅₀≤12 micromolar, 2 stars “**” denotescompounds with 12 micromolar <IC₅₀≤37 micromolar, one star “*” denotescompounds with 37 micromolar <IC₅₀≤111 micromolar, and 0 indicates acompound with IC₅₀>111 micromolar. A standard Tdp2 inhibition assay,such as the assay of Example 53, is used to determine the IC₅₀'s for thecompounds. LC methods are given in the General Methods section.

TABLE 1 Characterization and Enzymatic Inhibition Data for SelectedCompounds REC WCE LC retention TDP2 hTDP2 (method, Cpd Structure (μM)(μM) time in min) HRMS  1

* * A 8.2 284.0574  2

*** ** A 8.4 284.0551  3

* Not tested A 18.0  307.0590  4

0 Not tested A 21.8  NT  5

0 Not tested A 8.4 NT  6

0 Not tested NT NT  7

* * C 6.7 NT  8

0 Not tested A 7.4 256.0593  9

* * A 7.3 256.0613 10

** *** B 6.0 300.0499 11

** *** B 8.0 314.0653 12

** *** C 9.0 348.0499 13

** *** C 9.4 348.0514 14

** *** B 11.0  332.0563 15

** *** B 7.3 330.0604 16

0 Not tested A 8.5 331.0723 17

0 Not tested A 7.6 367.0501 18

0 Not tested A 6.8 347.0656 19

0 Not tested A 10.5  361.0817 20

0 Not tested A 7.5 307.0699 21

0 Not tested A 8.0 NT 22

*** ** B 8.1 392.0538 23

** *** B 13.0  368.0341 24

*** ** B 10.5  368.0335 25

0 Not tested B 15.4  382.0706 26

*** *** C 7.7 359.0679 27

*** *** B 13.6  368.0334 28

*** *** C 5.9 335.0673 29

* ** A 13.9  348.0865 30

** ** A 14.6  348.0887 31

** ** A 15.2  411.9820 32

* ** A 10.3  380.0543 33

** ** A 6.1 471.0920 34

*** *** C 10.1  457.1138 35

** *** A 10.4  352.0792 36

** ** A 8.8 368.0752 37

*** ** A 9.3 NT 38

*** *** A 14.9  394.0909 39

NT NT A 23.7  370.0704 40

* ** A 14.9  384.0864 41

** *** A 7.1 NT 42

** ** A 9.7 423.0923 43

** ** A 11.2  332.0544 44

** ** A 9.3 434.0334 59

* *** 60

* *** 61

* *** 62

** *** 63

** *** 64

** **** 65

* Not tested 66

** Not tested 67

** Not tested 68

** Not tested 69

** Not tested 70

*** Not tested 71

** Not tested 72

*** Not tested 73

**** Not tested 74

** Not tested

What is claimed is:
 1. A compound or pharmaceutically acceptable saltthereof of Formula I:

wherein X¹ is N or CR; X² is N or CR⁶; and at least one of X¹ or X² isN; R¹ is hydroxyl, C₁-C₆alkyl, C₁-C₆alkoxy, C₂-C₆alkenyloxy,C₂-C₆alkynyloxy, or C₃-C₇cycloalkyloxy, where one or more methyleneunits in the alkyl, alkenyl, or alkynyl portion of R¹ is optionally andindependently replaced with —O—, —S—, or —N(R⁷)—, and R¹ other thanhydroxyl is substituted by 0-3 substituents independently chosen at eachoccurrence from halogen, hydroxyl, cyano, ═N, ═NOR⁷, —CO₂H,—(CO)—O—C₁-C₆alkyl, —C(O)NR⁷R⁸, and —W—P(O)YR⁹ZR¹⁰; or R¹ is —O-A-Bwherein O is an oxygen atom; A is a linker consisting of a bond, analkylene chain of 1 to 6 carbons, or a phenylene group; B is a phenyl,or a 5 or 6 membered heterocycle having 1, 2, or 3 ring atomsindependently chosen from N, O, and S, wherein B is substituted with 0-3substituents independently chosen from halogen, hydroxyl, cyano, amino,—SH, C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl, C₁-C₆alkoxy, C₂-C₆alkanoyl,C₁-C₆thioalkyl, C₁-C₆haloalkyl, C₁-C₆haloalkoxy,—(C₀-C₆alkyl)cycloalkyl, —(C₀-C₆alkyl)CO₂H,—(C₀-C₆alkyl)-(CO)—O—C₁-C₆alkyl, —(C₀-C₆alkyl)C(O)NR⁷R⁸,—(C₀-C₆alkyl)NR⁷C(O)R⁸, —(C₁-C₆alkyl)alkoxy, —(C₁-C₆alkyl)OH,—(C₀-C₆alkyl)NR⁷R⁸, —SO₂—C₁-C₆alkyl, and —(C₀-C₆alkyl)-W—P(O)YR⁹ZR¹⁰; Y¹is O, NH, or S; Y² is N or C—R²; R² is hydrogen, halogen, C₁-C₆alkyl,C₁-C₆alkoxy, C₁-C₆haloalkyl, C₁-C₆haloalkoxy, —(C₀-C₆alkyl)cycloalkyl,—(C₀-C₆alkyl)NR⁷R⁸, or phenyl, each R² other than hydrogen and halogenbeing substituted with 0 to 3 groups chosen independently at eachoccurrence from halogen, hydroxyl, C₁-C₆alkyl, C₁-C₆alkoxy,C₁-C₆haloalkyl, and C₁-C₆haloalkoxy; or R² is a group -J-Q, where J is a1 to 4 carbon alkylene linker in which any —CH₂— group is optionallyreplaced by —C(O)O—, —C(O)NH—, —C(O)NR¹¹, or —C(O)—; Q is C₁-C₆alkyl,C₁-C₆alkylamino, aryl, or heteroaryl, each of which is unsubstituted orsubstituted with one or more groups independently chosen from halogen,hydroxyl, amino, cyano, C₁-C₄alkyl, C₁-C₄alkoxy, C₁-C₂haloalkyl, andC₁-C₂haloalkoxy; W, Y, and Z are independently at each occurrence a bondor O; R³, R⁴, R⁵, and R⁶, are chosen independently at each occurrencefrom hydrogen, halogen, cyano, amino, C₁-C₆alkyl,—(C₀-C₆alkyl)cycloalkyl, C₁-C₆alkoxy, C₁-C₆haloalkyl, andC₁-C₆haloalkoxy; R⁷, R⁸, R⁹ and R¹⁰ are chosen independently at eachoccurrence from hydrogen, C₁-C₆alkyl, C₂-C₆alkenyl,—(C₀-C₆alkyl)cycloalkyl, and C₁-C₆haloalkyl, and any R⁷ and R⁸ bound tothe same nitrogen atom may be taken together to form a 4- to 7-memberedheterocyloalkyl group substituted with 0 to 2 substituents chosen fromhydroxyl, halogen, C₁-C₄alkyl, C₁-C₄alkoxy, and C₂-C₄alkanoyl; and R¹¹is C₁-C₆alkyl or C₁-C₆alkylamino-; wherein the compound is not:


2. The compound or salt of claim 1, wherein Y¹ is O.
 3. The compound orsalt of claim 1 wherein R¹ is hydroxyl, C₁-C₈alkoxy or—O—(C₀-C₆alkyl)cycloalkyl, in which one or more methylene units in thealkoxy or alkyl portion of R¹ is optionally and independently replacedwith —O— or —N(R⁷)—, and R¹ is substituted by 0-3 substituentsindependently chosen at each occurrence from hydroxyl, halogen, cyano,—CO₂H, —(CO)—O—C₁-C₆alkyl, and —W—P(O)YR⁹ZR¹⁰; or R¹ is the group—O-A-B; B is a phenyl, or a 5 or 6 membered heteroaryl having 1, 2, or 3Nitrogen ring atoms, wherein B is optionally substituted with 0-3substituents independently chosen from halogen, hydroxyl, cyano, amino,C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl, C₁-C₆alkoxy, C₂-C₆alkanoyl,C₁-C₆haloalkyl, C₁-C₆haloalkoxy, —(C₀-C₆alkyl)cycloalkyl,—(C₀-C₆alkyl)CO₂H, —(C₀-C₆alkyl)-(CO)—O—C₁-C₆alkyl, —(C₁-C₆alkyl)alkoxy,—(C₁-C₆alkyl)OH, —SO₂—C₁-C₆alkyl, and —(C₀-C₆alkyl)-W—P(O)YR⁹ZR¹⁰; R² ishalogen, C₁-C₆alkyl, C₁-C₆haloalkyl, —(C₀-C₆alkyl)cycloalkyl, or phenyl,said phenyl being substituted with 0 to 3 groups chosen independently ateach occurrence from halogen, hydroxyl, C₁-C₆alkyl, C₁-C₆alkoxy,C₁-C₆haloalkyl, and C₁-C₆haloalkoxy.
 4. The compound or salt of any oneof claims 1 to 3 wherein R³ and R⁴ are both hydrogen.
 5. The compound orsalt of any one of claims 1 to 4, wherein R² is hydrogen, halogen,C₁-C₆alkyl, C₁-C₆alkoxy, C₁-C₆haloalkyl, C₁-C₆haloalkoxy,—(C₀-C₆alkyl)cycloalkyl, —(C₀-C₆alkyl)NR⁷R⁸, or phenyl, each R² otherthan hydrogen and halogen being substituted with 0 to 3 groups chosenindependently at each occurrence from halogen, hydroxyl, C₁-C₆alkyl,C₁-C₆alkoxy, C₁-C₆haloalkyl, and C₁-C₆haloalkoxy.
 6. The compound orsalt of claim 5, wherein R² is C₁-C₆alkyl, C₁-C₆haloalkyl,—(C₀-C₆alkyl)cycloalkyl, or phenyl, said phenyl being substituted with 0to 3 groups chosen independently at each occurrence from halogen,hydroxy, C₁-C₆alkyl, C₁-C₆alkoxy, C₁-C₆haloalkyl, and C₁-C₆haloalkoxy.7. The compound or salt of any one of claims 1 to 4, wherein R² is

where n is 1, 2, 3, or 4; J¹ is O, NH, NR¹¹; Q¹ is C₁-C₆alkyl, orC₁-C₆alkylamino-; R¹² is absent or 1 or more substituents independentlychosen from hydroxyl, halogen, amino, or cyano; R¹³ is absent or 1 or 2substituents independently chosen from C₁-C₄alkyl, and mono- ordi-C₁-C₆alkylamino.
 8. The compound or salt of any one of claims 1 to 7wherein R¹ is substituted with at least one —W—P(O)YR⁹ZR¹⁰ substituent;and W is a bond; and Y and Z are both O.
 9. The compound or salt of anyone of claims 1 to 8 wherein R² is methyl or phenyl.
 10. The compound orsalt of any one of claims 1 to 9 wherein X¹ is N; and X² is CH.
 11. Thecompound or salt of any one of claims 1 to 9 wherein X¹ is CH; and X² isN.
 12. The compound or salt of any one of claims 1 to 11 wherein R¹ isC₁-C₈alkoxy.
 13. The compound or salt of any one of claims 1 to 11wherein R¹ is a phenoxy or pyridyloxy, each of which is optionallysubstituted with 0-3 substituents independently chosen from halogen,hydroxyl, cyano, C₁-C₆alkyl, C₂-C₆alkenyl, C₂-C₆alkynyl, C₁-C₆alkoxy,C₁-C₆haloalkyl, C₁-C₆haloalkoxy, —(C₀-C₆alkyl)cycloalkyl,—(C₀-C₆alkyl)CO₂H, —(C₀-C₆alkyl)-(CO)—O—C₁-C₆alkyl, —(C₁-C₆alkyl)alkoxy,—(C₁-C₆alkyl)OH, —SO₂—C₁-C₆alkyl, and —(C₀-C₆alkyl)-W—P(O)YR⁹ZR¹⁰. 14.The compound or salt of any one of claims 1 to 11, wherein R¹ is alkoxywhere one or more methylene units in the alkyl portion of R¹ isoptionally replaced by —O— or —N(R⁷)— and R¹ is substituted with 1 to 3substituents independently chosen from hydroxyl and —WP(O)YR⁹ZR¹⁰; whereW is a bond; and Y and Z are both O.
 15. The compound or salt of any oneof claims 1 to 11, wherein R¹ is —O-A-B.
 16. The compound or salt ofclaim 15, wherein A is a bond or an alkylene chain of 1 to 3 carbonatoms; and B is phenyl or pyridyl optionally substituted with 0-3substituents independently chosen from halogen, hydroxyl, cyano,C₁-C₄alkyl, C₁-C₄alkoxy, C₂-C₄alkanoyl, C₁-C₂haloalkyl, C₁-C₂haloalkoxy,—(C₀-C₂alkyl)-(CO)—O—C₁-C₆alkyl, —(C₀-C₂alkyl)C(O)NR⁷R⁸,—(C₀-C₂alkyl)NR⁷C(O)R⁸, —(C₁-C₆alkyl)OH, and —SO₂—C₁-C₂alkyl.
 17. Thecompound or salt of claim 16, wherein A is a bond; and B is phenylsubstituted with one substituent chosen from hydroxyl, halogen, andcyano.
 18. The compound or salt of claim 15, wherein B is a triazolyl,pyrazolyl, imidazolyl, thienyl, dioxylanyl, morpholinyl, piperazinyl, orpiperidinyl group; each of which B is substituted with 0-3 substituentsindependently chosen from halogen, hydroxyl, cyano, amino, C₁-C₆alkyl,C₂-C₆alkenyl, C₂-C₆alkynyl, C₁-C₆alkoxy, C₂-C₆alkanoyl, C₁-C₂haloalkyl,C₁-C₂haloalkoxy, —(C₀-C₆alkyl)CO₂H, —(C₀-C₆alkyl)-(CO)—O—C₁-C₆alkyl,—(C₀-C₆alkyl)C(O)NR⁷R⁸, —(C₀-C₆alkyl)NR⁷C(O)R⁸, —(C₁-C₆alkyl)OH,—(C₀-C₆alkyl)NR⁷R⁸, and —SO₂—C₁-C₆alkyl; where R⁷ and R⁸ are hydrogen orC₁-C₄alkyl.
 19. The pharmaceutical composition comprising a compound orsalt of any one of claims 1 to 18, together with a pharmaceuticallyacceptable carrier.
 20. The method of treating cancer, comprisingadministering a therapeutically effective amount of a compound or saltof any one of claims 1 to 18, to a patient in need of such treatment.21. The method of claim 20, additionally comprising determining thecancer responds to tyrosyl-DNA phosphodiesterase 2 (Tdp2) inhibition.22. The method of claim 20, additionally comprising administering thecompound of any of claims 1 to 18 in combination with one or moreadditional compounds, wherein at least one of the additional compoundsis an active agent known to be an inhibitor of topoisomerase 2, to apatient in need of such treatment.
 23. The method of claim 20,additionally comprising administering a therapeutically effective amountof a compound or salt of any of claims 1 to 18, in combination with oneor more additional compounds, wherein at least one additional compoundis an active agent chosen from etoposide, teniposide, doxorubicin,daunorubicin, mitoxantrone, amsacrine, ellipticines, aurintricarboxylicacid, and3-hydroxy-2-[(1R)-6-isopropenyl-3-methyl-cyclohex-2-en-1-yl]-5-pentyl-1,4-benzoquinone(HU-331), to a patient in need of such treatment.
 24. The method ofclaim 20, wherein the cancer is glioma (glioblastoma), acute myelogenousleukemia, acute myeloid leukemia, myelodysplastic/myeloproliferativeneoplasms, sarcoma, chronic myelomonocytic leukemia, non-Hodgkin'slymphoma, astrocytoma, melanoma, non-small cell lung cancer, small celllung cancer, cervical cancer, rectal cancer, ovarian cancer,cholangiocarcinomas, chondrosarcoma, or colon cancer.